Spinning a Magnet Creates another Magnet - A Handmade Quantum System Paves the Way for High-Precision Quantum Operations -

CHUDO hiroyukiR.G. for Spin-energy Science

A collaborative research group including Hiroyuki Chudo, Principal Researcher of the Spin-Energy Science Research Group at the Advanced Science Research Center, has discovered that mechanical rotational motion can lead to the multiplication of nuclear spin degrees of freedom.
Conventionally, for spin-1/2 systems, resonance occurs only between the up-spin and down-spin states, resulting in the observation of a single signal. However, using a uniquely developed device that observes nuclear magnetic resonance (NMR) signals in the same rotating frame of reference as the rotating sample, we observed a surprising result: despite dealing with spin-1/2 nuclei, the signal split into three distinct lines. These three signals correspond to energy absorption between four split energy states. To explain this phenomenon, it is necessary to consider the presence of two spin-1/2 systems. In other words, it is believed that the rotational motion of the sample gave rise to an additional degree of freedom equivalent to another spin-1/2.
This spin multiplication originates from the temporal periodicity induced by rotating the sample in a magnetic field. Using Floquet theory—a theoretical framework that deals with time-periodic systems—we analyzed the spin states in this experiment. The analysis theoretically demonstrated that, in addition to the original spin-1/2 degree of freedom of fluorine nuclei, a new spin-1/2 degree of freedom arising from the rotational motion is generated.
Furthermore, it was theoretically shown that these two spin-1/2s are equivalent to two quantum bits (qubits), which are the fundamental units of information in quantum information processing. Quantum operations using this combination of a single nuclear spin and the newly emergent spin induced by rotation do not require the coupling of two distinct physical systems, which is typically necessary. As a result, it is expected that this method can significantly reduce implementation errors and enable high-precision quantum operations.
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New Acoustic Wave Phenomenon Discovered: Opening Doors to Next-Generation Communication Devices

YAMAMOTO　KeiR.G. for Spin-energy Science

Kei Yamamoto from Research Group for Spin-Energy Science and his collaborators in Tohoku University discovered a novel diffraction phenomenon of surface acoustic waves (SAWs), which travel along the surface of materials and are indispensable for modern communication technologies, including freuquency filters and sensors. Known as "nonreciprocal diffraction", this effect occurs when SAWs propagate through a nanoscale array of magnetic materials.
While nonreciprocal diffraction had previously been observed only in optics, this marks the first time it has been confirmed in other wave phenomena beyond optics. This finding may enable precise control of SAW propagation paths using magnetic fields, leading to the development of innovative acoustic devices that advance both classical and quantum communication technologies.
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Neutron beams and nanotechnology as weapons to control "devil's invented surfaces"
- A new future for catalytic converters by overcoming the challenges of ceramics manufacturing technology -

AOYAGI Noboru, IKEDA-OHNO AtsushiR.G. for Sustainable Functional Materials Science

A research team led by Noboru Aoyagi, the associate research principal of Research Group for Sustainable Functional Materials Science at Advanced Science Research Center, has succeeded in layering nanoparticle agglomerates, which have been described as "devil's invented surfaces". Ceramics are attracting attention as functional materials because they are less susceptible to corrosion than metal nanoparticles, have excellent heat and radiation resistance, and can be used stably. In this study, the research team investigated the material production process for exhaust gas purification catalysts and they discovered that small nanoparticles (primary particles) also form, although it was thought that only liquids with metal complexes exist in the initial stages of the reaction. They also discovered that the primary particles regularly assemble over time to form slightly larger particles (secondary particles) that can stack into freely variable higher order structures by changing the shape of the liquid droplet and the drying method.
This finding is the first explicit example of the importance of surface interactions for self-assembling structures. In the future, taking into account the properties of self-assembling structures, ceramic nanoparticles with excellent environmental resistance could lead to the development of functional materials from a new perspective and contribute to technologies that reduce environmental pollution in our country.
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Manipulating the Geometry of 'Electron Universe' in Magnets

ARAKI Yasufumi, IEDA Jun'ichiR.G. for Spin-energy Science

Y. Araki and J. Ieda from R.G. for Spin-Energy Science and their collaborators in Tohoku University successfully manipulated the quantum metric of electrons in a room-temperature magnet by the tabletop experiment for the first time in the world. The quantum metric is the structure of quantum state, which is regarded as the structure of "electron universe" governing the electrons' motion. Using the chiral antiferromagnet with the spins aligned in a triangular pattern, they experimentally observed an unconventional electric conduction following the applied magnetic field.
With the analyses of the theoretical model, this unconventional conduction was identified as the outcome of the quantum metric manipulated by the magnetic field.
The findings give a fundamental idea to understand and make use of the electric conduction originating from the quantum metric, which may offer new opportunities to develop functional devices such as rectifiers and detectors in the future.
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The Mystery of the Earth! What is the secret of metals in the soil?
- Molecular Scale Simulations and Observations Reveal the Properties of Soil

TANAKA KazuyaR.G. for Sustainable Functional Materials Science

The research team, where Manager Kazuya Tanaka of Research Group for Sustainable Functional Materials Science at the Advanced Science Research Center participates, analyzed the adsorption behavior of metal ions using a combination of molecular-level experiments and supercomputer simulations and found that metal ions that are less soluble in water and have larger ionic radii tend to be more strongly adsorbed on clay minerals.
This finding will not only help to understand the behavior of radioactive elements in soil when considering the disposal of radioactive waste, but is also expected to contribute to resource exploration, understanding of planets in the solar system other than Earth (such as Mars) and asteroids (such as Ryugyu), and improving the efficiency of agriculture that handles soil.
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Perspective of tiny amount of carbon inside steel
-Development of a new non-destructive quantification analysis method for light elements by using muon-

HIGEMOTO WataruR.G.for Surface and Interface Science

A research team, where Wataru Higemoto and Takashi U Ito of the Surface and Interface Science Research Group at the Advanced Science Research Center are included, has developed a method to non-destructively identify an amount of carbon contained in steel by using muons, which is one of quantum beam.
The research team used the world's most intense muon beam delivered from the high-intensity proton accelerator facility, J-PARC, Materials and Life Science Experimental Facility (MLF), Muon Science Experimental Facility (MUSE), and succeeded position-selectively and non-destructively in analyzing tiny amounts of carbon inside steel by using muon at the first time in the world. The lifetime of a muon in a material depends on the captured element. By utilizing this property, it has become possible to detect tiny amounts of carbon contained in steel with high sensitivity.
The results of this research will provide a new option as muon analysis, for qualitative control of steel, one of the most important substances for humankind, and will also provide a new analysis method for valuable materials such as cultural properties.
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Revealing pairing state of spin-triplet superconductor
- unprecedented superconductivity : similarity to helium-3 superfluidity -

HAGA YoshinoriR.G. for Strongly Correlated Actinides Science

A research group including Dr. Yoshinori Haga from R. G. for Strongly Correlated Actinide Science, in collaboration with Kyoto university has conducted thermal conductivity measurements in the superconducting state of UTe2, a candidate of a spin-triplet superconductor.
The result strongly indicates the possibility of a topological superconductivity in this compound. In this case, a Majorana quasiparticle appearing on the superconducting surface can play a key role in the next-generation quantum computer.
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Turning radioactive waste into a “treasure trove”
-Use in storage batteries and power generation, recovery of platinum group elements

IEDA Jun'ichiR.G. for Spin-energy Science

The project of the JAEA Recycling Special Research Team, in which J. Ieda from R.G. for Spin-energy Science participates, to recover energy and useful elements from radioactive waste has been featured in various news outlets.
In this project, we are in charge of recovering thermal energy from radioisotopes using spin thermoelectric power generation, and have demonstrated through various radiation experiments that thermoelectric conversion characteristics do not deteriorate even in high radiation environments.
This result has the potential to provide a new approach to the treatment of radioactive waste, which is one of the challenges of modern society, and we plan to continue research and development to increase power output.

Why are uranium-based superconductors tough in magnetic fields?
-Success in observing magnetic fluctuations that reinforce superconductivity -

TOKUNAGA YoR.G. for Strongly Correlated Actinides Science

The research team, led by Group Leader Yo Tokunaga of the Research Group for Strongly Correlated Actinide Science at the Advanced Science Research Center, conducted nuclear magnetic resonance (NMR) experiments in high magnetic fields on a uranium-based superconductor, a potential candidate for spin-triplet superconductivity.
The study elucidated the mechanism behind the high upper-critical field exhibited by superconductivity in the uranium-based superconductor. In the material, applying a strong magnetic field increases magnetic fluctuations, reinforcing the pairing of electron pairs that leads to superconductivity and achieves the high upper critical field. This achievement suggests the possibility of developing superconductors with even higher critical magnetic fields in compounds beyond uranium, expanding the applications of superconducting technology.
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Ulstrasonic diagnosis of hidden magnetic order
- New route towards materials search for high-speed magnetic memory -

YAMAMOTO KeiR.G. for Spin-energy Science

K. Yamamoto from R. G. for Spin-energy Science and his collaborators in RIKEN have successfully demonstrated that ultrasound offers a new method to investigate a type of magnetic materials called antiferromagnets which are difficult to study by the conventional magnetic field probes.
Ordinary magnets consist of atoms carrying magnetic moments that are all aligned parallel to exhibit a macroscopic magnetic moment. In antiferromagnetic materials, constituent atoms individually carry magnetic moments, but their direction alternates one atom after another such that the total magnetic moment completely vanishes. This peculiar magnetic ordering implies the antiferromagnetic structure much more rigid than ordinary magnets, making them suitable for rapid magnetic moment reversal required for high-speed magnetic memory devices. The lack of total magnetic moment is a double-edged sword, however, as it means antiferromagnets do not respond to magnetic fields easily and therefore are difficult to study and control. The present research establishes ultrasound waves as an alternative way to detect and manipulate the antiferromagnetically ordered magnetic moments. This discovery can accelerate the research into antiferromagnetic materials for next-generation information technologies.
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Sound waves spin in magnetic triangles
- New detection scheme of acoustic wave rotation via specially designed artificial lattice -

YAMAMOTO KeiR.G. for Spin-energy Science

K. Yamamoto from R. G. for Spin-energy Science and his colloaborators in RIKEN have designed an artificial lattice pattern made of triangluar shaped magnets and successfully generated rotating wave fronts of surface acoustic waves propagating through the pattern.
The acoustic waves with rotating wave fronts are said to have valley degrees of freedom according to whether the rotation is right-handed or left-handed. By assigning 0 and 1 to the two rotating states, the valley degrees of freedom are potentially useful as an underlying principle for novel computational devices that can save energy and be more resistant to heat or radiation compared to the current semi-conductor-based technologies. The present research demonstrates that applying magnetic field can resolve the valley degrees of freedom and selectively extract either left- or right-handed acoustic waves, which will provide a solid platform for further investigations in controlling the valley using artificial lattice structures.
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New Metal Nanoparticle-Zeolite Composite Catalyst Developed for Direct Coupling of Alkanes and Benzene
―Achieving high efficiency in reactions through proximity of acid sites and Pd particles―

ITO TakashiR.G.for Surface and Interface Science

A research group, including T. Ito from R.G. for Surface and Interface Science has developed a catalyst that supports Pd nanoparticles on the outer surface of zeolite and has achieved a direct coupling reaction between alkanes and benzene with high efficiency using this catalyst.
In contrast to conventional alkylbenzene synthesis, which emits acid as a byproduct, that created through this method is only hydrogen or water. In this reaction, the transfer of hydrogen atoms from the acid sites of zeolite to Pd nanoparticles is considered important. Our μ+SR studies on muonium, a pseudo-isotope of hydrogen, in zeolite suggest that when atomic hydrogen is generated in zeolite, it can maintain the atomic state for the time required for the reaction.
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How heat from a gas is transferred to a solid?
- Elucidation of heat transfer process between gas and solid, toward a new way of controlling heat transfer -

UETA HirokazuR.G.for Surface and Interface Science

H. Ueta and K. Fukutani (The University of Tokyo, Institute for Industrial Science) from R.G. for Surface and Interface Science have clarified the mechanism of rotational-energy transfer from hydrogen molecule to a solid surface.
The present research indicates the possibility of controlling the heat transfer from gas to solid by changing the elements and structure of the topmost surface of the solid.
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Step Unbunching of SiC
- New technology for the atomically flat surface of semiconductors -

TERASAWA Tomo-oR.G.for Surface and Interface Science

T. Terasawa (Research Group for Surface and Interface Science) and collaborators at Waseda Univerisity and Nagoya University have discovered a step unbunching phenomenon that can be applied as a new technology flattening semiconductor surfaces at the atomic level.
Conventional semiconductor fabrication technologies have the problem of flattening the SiC surface, that a damaged layer remains due to processing or the surface becomes rough without a damaged layer, which adversely affects device characteristics. The present results are expected to eliminate the chemical-mechanical polishing processes in the semiconductor manufacturing process to significantly reduce costs and time.
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New principle for drastic miniaturization of inductor by 10,000 times
- To reduce size and power consumption of electronic circuits toward "Internet of Things" -

ARAKI YasufumiR.G.for Spin-energy Science

Y. Araki and J. Ieda from R.G. for Spin-Energy Science have established a new principle to drastically miniaturize an 　inductor, which is an element essential in electronic circuits.
This new type of inductor is composed of thin films of topological insulators, and can be downsized by 10,000 times compared with the conventional inductor composed of a coil, while keeping its power efficiency. This new principle is derived based on the magnetoelectric response characteristic to the interface of topological insulator. This work serves as the theoretical basis for integration of high-frequency electronic circuits using inductors. It can play a decisive role in implementing information processing technology in various electronic devices, which is essential in realizing the "Internet of Things" society.
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Chiral superconductivity in uranium compound

HAGA YoshinoriR.G.for Strongly Correlated Actinides Science

Yoshinori Haga and the collaborators in ASRC, University of Tokyo and Tohoku University have shown experimentally that chiral superconductivity is realized in a uranium compound UTe2.
Present discovery is important in understanding the fundamental properties of unconventional superconductivity and the possible application to quantum mechanical technologies arising from peculiar characteristics of chiral superconductivity.
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Novel Superconducting State Found in Ultra-Clean Single Crystal of Uranium-Based Superconductor
―Change in superconducting properties with a magnetic field―

SAKAI HironoriR.G.for Strongly Correlated Actinides Science

Hironori Sakai and his colleagues in the Research Group for Strongly Correlated Actinides Science in the Advanced Science Research Center have discovered a new intermingled superconducting state of low-field and high-field superconductivity.
Last year, they developed a new growth method for ultra-clean single crystals of UTe2, significantly improving its superconducting performance. This study used the ultra-clean crystal to precisely investigate its superconducting properties while changing the magnetic field and temperature. Further research aimed at developing methods to control various superconducting states, including low-field, high-field, and mixed SC states, is expected to create new quantum devices for next-generation quantum computers.
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Quantum Electrodynamics Verified with Exotic Atoms

HASHIMOTO TadashiR.G.for Hadron nuclear physics

An international collaboration of researchers, including Tadashi Hashimoto (Advanced Science Research Center, Japan Atomic Energy Agency), has succeeded in a proof-of-principle experiment to verify strong-field quantum electrodynamics with exotic atoms, by performing high-precision measurements of the energy spectrum of muonic characteristic X-rays emitted from muonic atoms using a state-of-the-art X-ray detector.
The group's results are a significant step toward verifying fundamental physical laws under strong electric fields, which humankind has not yet been able to create artificially. The highly efficient and accurate X-ray energy determination method using state-of-the-art quantum technology demonstrated in this research is expected to be applied to various research fields, such as non-destructive elemental analysis methods using muonic atoms.
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Magnonic Casimir effect in magnets

NAKATA KoukiR.G.for Spin-energy Science

SUZUKI KeiR.G.for Advanced Theoretical Physics

Kouki Nakata and Kei Suzuki (Advanced Science Research Center, Japan Atomic Energy Agency) have theoretically proposed a magnonic analog of the Casimir effect, which they call the magnonic Casimir effect.
Quantum fluctuations are the key concepts of quantum mechanics. Quantum fluctuations of photon fields induce a shift of the zero-point energy under spatial boundary conditions, where the resultant quantum phenomenon is called the Casimir effect. While the Casimir effect for photon fields has been studied for a long time, an analogous effect is expected to be induced also by other quantum fields.
In their work, they have focused on magnon fields inside thin films of magnets and studied not only an antiferromagnetic insulator, chromium(III) oxide, but also a ferrimagnetic insulator, yttrium iron garnet (YIG). Thus, they have theoretically revealed the magnonic Casimir effect in these magnets and found that the magnonic Casimir energy corresponds to an energy originated by reducing the thickness of magnets.
Their result suggests that YIG, the key ingredient of magnon-based spintronics, can serve also as a promising platform for manipulating and utilizing Casimir effects, called the Casimir engineering. Microfabrication technology can control the thickness of thin films and realize the manipulation of the magnonic Casimir effect. Thus, they have paved the way for magnonic Casimir engineering.
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How do graphene and gold shake electron hands?
-Manipulating the chemical bond between graphene and gold by the arrangement of gold atoms toward the realization of energy-saving integrated circuits-

TERASAWA Tomo-oR.G.for Surface and Interface Science

A research group including Tomo-o Terasawa (Advanced Science Research Center, Japan Atomic Energy Agency) revealed that the atom arrangement of gold dominates the chemical bonding between graphene and gold.
When graphene, a chemically inert carbon film, touched gold, it was known that a chemical bond formed under certain conditions. However, the bond formation mechanism has not been understood. The researchers observed the "electron hand," or electron orbital, with the irradiation of ultraviolet light on the interface between gold and graphene. They found that the periodicity of gold atoms and the orientation between gold and graphene affect the type of "electron hands" of gold. The chemical bonding is expected to transfer the spin polarization, the magnetism source, from gold to graphene. The results of this research will be important for applying the spin polarization in graphene to next-generation energy-saving integrated circuits and other applications.
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J-PARC experiment created an exotic, highly unstable particle and measured its mass

HASHIMOTO TadashiR.G.for Hadron nuclear physics

International research group including Tadashi Hashimoto (Advanced Science Research Center, Japan Atomic Energy Agency) succeded in synthesizing Λ(1405) for the first time by combining a K- meson and a proton in the experiment they carried out at the J-PARC accelerator.
This work implies that Λ(1405) is an unusual state consisting of four quarks and one antiquark, and does not fit the conventional classification in which particles have either three quarks or one quark and one antiquark. This work may lead to a better understanding of the interior of ultra-dense neutron stars.
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First successful observation of spin fluctuations in real space
- Elucidation of nanometer-size magnetism to improve the functionality of ultra-small magnetic devices -

SHAMOTO ShinichiR.G.for Surface and Interface Science

Shinichi Shamoto, a visiting researcher (Advanced Science Research Center, Japan Atomic Energy Agency), and his team succeeded in observing spin fluctuations in real space for the first time in the world.
The magnetism of a magnet is expressed by the "spin" of electrons. This "fluctuation" of the spin is related to the magnet's performance, but when it is miniaturized to the nanometer size, it becomes a weak signal that is difficult to detect, and so far, there has been no example of direct real space observation in experiments. An intense neutron beam is required to observe nanometer-sized spin fluctuations. Therefore, by using a high-intensity pulsed neutron beam at J-PARC Materials and Life Science Experimental Facility and using a newly developed analysis program, they have realized the direct real-space observation of spin fluctuations for the first time in the world. By using the analysis method developed this time, it will be possible to elucidate the spin fluctuations in the nanometer-size magnets, and it is expected to contribute to the functional improvement of nanomagnetic materials.
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Observation of tiny magnetism deep in the superconducting state probed by muon
-Progress toward clarification of a mechanism of superconductivity-

HIGEMOTO WataruR.G.for Surface and Interface Science

A research group including Wataru Higemoto (Advanced Science Research Center, Japan Atomic Energy Agency) has found magnetically ordered state deep in the superconducting state.
Mechanism of superconductor is long standing problem. In particular, role of magnetism for a superconductivity is still veiled issue. By using muon at J-PARC, they have investigated relation between magnetism and superconductivity in high quality specimen of cerium based superconductor CeCo(In,Zn)5. As a result, phase transition between non-magnetic to magnetic state is successfully observed.Present results demonstrate that magnetism deep inside the superconducting state strongly affects the superconductivity.
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The first determination of the Ra hydration structure
-The beginning of molecular level research on Ra-

TANAKA KazuyaR.G.for Sustainable Functional Materials Science

A research group including Kazuya Tanaka (Advanced Science Research Center, Japan Atomic Energy Agency) has successfully determine the Ra hydration structure using EXAFS at SPring-8.
The ab initio molecular dynamics simulations also revealed that the water molecules in the first hydration shell of Ra are less structured and more mobile than those of Ba, which is an analogous element of radium.
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Study of repulsive core between quarks via the Σ-proton elestic scattering

YAMAMOTO TakeshiR.G.for Hadron nuclear physics

International research group including Takeshi Yamamoto (Advanced Science Research Center, Japan Atomic Energy Agency) has found strong repulsive core between hyperon and proton by generating quark Pauli forbidden state via the Σ-proton elastic scattering.
This observation gives strength of the repulsive core and information of its origin. It is expected that the result will deepen our understanding of extended nuclear forces including new quarks and also the reason why matters can exist stably.
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Sieving hydrogen isotopes through monolayer graphene
-Demonstration of new technique for low-cost purification of deuterium gas-

YASUDA SatoshiR.G.for Surface and Interface Science

Research Groups for Surface and Interface Sceince demonstrated that hydrogen and deuterium can be separated using a single layer graphene.
Experimental and theorytical approaches proved that the separation mechanism originates from quantum tunneling effect of hydrons through the graphene. The findings provides us with solid verification of the separation mechanism of graphene, where the mechanism is still controversial, and a new economical methodology of enrichment of hydrogen isotopes for a wide range of industrial fields such as nuclear fusion energy, semiconductor, biochemistry, and medicals.
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Determination of the magnetic energy landscape for nanomagnets
ーA step forward to high-performance pseudo-quantum computers-

IEDA Jun'ichiR.G.for Spin-energy Science

A joint research team of Tohoku University and Japan Atomic Energy Agency has elucidated the mathematical formula describing the stochastic behavior of nanometer-sized magnets (nanomagnets) under a current/field bias through experiments, establishing an essential foundation for the development of spintronic probabilistic computers and ultra-low power consumption semiconductors that can handle complex computational problems with low power consumption.
https://rdcu.be/cTSds
https://www.nature.com/articles/s41467-022-31788-1

Success in growing high-purity uranium superconductors with familiar salt!
ーHopes for potential application to next-generation quantum computers

SAKAI　Hironori
R.G.for Strongly Correlated Actinides Science

Research group for the Strongly Correlated Actinide Science (Advanced Science Research Center, Japan Atomic Energy Agency) has developed a new crystal growth method for a uranium superconducting material and succeeded in significantly improving the purity of the crystal and its superconducting performance.
Uranium ditelluride (chemical formula UTe2) is a candidate topological superconductor that is expected to be applied to next-generation quantum computers. Although pure single crystals are needed to improve superconducting performance, a slight elemental defects were unable to be removed for a long time. The researchers succeed in obtaining high purity crystals without any elemental defects by developing a crystal growing method using molten salt, which is a quite familiar material. The purification of crystals improves superconducting performance and contributes to the acceleration of research on topological superconductivity, which is expected to be applied to quantum computers.
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How does the superdeformed state in nuclei decay?
―Mixing of three shapes in 40Ca plays an unexpected role

UTSUNO Yutaka
R.G.for Advanced Theoretical Physics

A joint research group including Advanced Science Research Center finds an extraordinarily hindered electromagnetic decay from the superdeformed state to the spherical ground state in the calcium-40 nucleus.
Theorerical calculations suggest that this hindrance is caused by a quantum interference effect that is unique to the mixing of three different shapes. This result possibly impacts on understanding how the shapes of nuclei are created and their relation to the evolution of magic numbers.
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Exploring the origin of carbon with the supercomputer Fugaku
―First-principles calculation reveals alpha-cluster structure

UTSUNO Yutaka
R.G.for Advanced Theoretical Physics

It is demonstrated by a joint research group including Advanced Science Research Center that an excited state of carbon-12, known as the Hoyle state, consists of alpha clustering by means of first-principles nuclear-structure calculations.
The Hoyle state plays a decisive role in the synthesis of carbon in stars, and hence this finding greatly contributes to elucidating the origin of carbon that is essential in life.
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Topological physics stepped towards energy-efficient magnetic recording technologies

ARAKI Yasufumi
R.G.for Spin-energy Science

A joint research team of Hokkaido University and Japan Atomic Energy Agency demonstrated a new principle of magnetization reversal based on a special electronic state called the Weyl point of the oxide magnet strontium ruthenate (SrRuO3).
This new principle enables magnetization manipulation with higher efficiency than before, contributing to ultra-low-power magnetic memory applications in the future.
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Unwinding the "twist" of inductors -New development in power control research with the quantum relativistic effect of electron spins-

IEDA Jun'ichi
R.G.for Spin-energy Science

A joint research team of Tohoku University and Japan Atomic Energy Agency proposed a new inductor principle using spin-Berry phase in spintronics technology.
This finding clarifies that the inductor function can be realized by standard magnetic materials without "twisting" like conventional coils and magnetic spiral structures, enabling to make small elements that are difficult with conventional technology and variable inductors that do not use mechanical operating parts.
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The sound of spin, played with ultrasonic waves and listened with neutrons
- Identify the efficiency factor of spin-driven power generation -

IEDA Jun'ichi
R.G.for Spin-energy transformation Science

A joint research team of CROSS, Niigata University, and Japan Atomic Energy Agency developed a new experimental method combining ultrasound injection and neutron scattering, whereby the team clarified that it is important to design materials that support a large spin-lattice coupling for improving the efficiency of the "spin-seebeck effect," which is the principle of generating electricity using spins in solids.
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Innovation in the study of the strong interaction brought with a high-intensity accelerator and an ultra-high precision "thermometer”

HASHIMOTO Tadashi
R.G.for Hadron nuclear physics

International research group including Tadashi Hashimoto (Advanced Science Research Center, Japan Atomic Energy Agency) has measured X-rays from kaonic atoms produced at J-PARC using a high-resolution X-ray detector based on a highly-sensitive "thermometer".
This kind of X-ray detector was used in a high-intensity secondary hadron beam line for the first time. As a result, the X-ray energies were determined with 10 times better precision than before, which gives a stringent constraint on the strong-interaction model between a kaon and a nucleus. The X-ray measurement technique, developed in this work for high radiation environments, would bring innovations in many scientific fields.
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Advancement in understanding the reaction mechanism to produce extreme nuclei
- Toward the island of stability in the heaviest element region -

NISHIO Katsuhisa
R.G.for Heavy element nuclear science

Research group for Heavy Element Nuclear Science has successfully quantified the angular momentum of the excited compound nuclei populated in the "multinucleon transfer (MNT) reaction".
This is the reaction expected to produce neutron-rich superheavy nuclei. The angular momentum as the important quantity to determine the cross section to produce these nuclei is, however, scarecely investigated so far. The present results deliver an important information to understand the mechanism of the MNT reacion, a promising method to explore the new region of the chart of nuclei.
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Discovery of 'Multippole Polaron': Electrons motion largely influenced by spin and orbital degree of freedom

HAGA Yoshinori
R. G. for Material Physics in Heavy Element Systems

Group of researchers including Yoshinori Haga (Advanced Science Research Cetner, Japan Atomic Energy Agency) discovered a new type of quasiparticle "multipole polaron" which emerges under strong interaction between conduction electrons and multipoles (entangled spin and orbital degrees of freedom) in the phase trasition known as "Devil's staircase".
In Devil's staircase, the arrangement of spins and orbitals changes as functions of temperature or magnetic field. It was found that multipole polaron also modifies the interaction in accordance with the Devil's staircase. The present observation is also important in the context of spintronics-based magnetic material research, since the change of the multipole polaron under external field such as magnetic field or pressure can be potentially used for a new type of spintronics devices like magnetic memories.
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New principle for significant reduction of power consumption in spintronics-Approach to material development for "electric manipulation of magnetism"-

ARAKI Yasufumi
R.G.for Spin-energy transformation Science

Research Group for Spin-energy Transformation Science has discovered a new principle to manipulate magnetism of magnets electrically.
Whereas the conventional method uses an electric current and suffers from power consumption due to electric resistivity, the new principle enables manipulation of magnetism by an electric voltage, which relies on "topology" structure of electrons in the material and is insensitive to electric resistivity.The new principle solves the origin of the highly efficient manipulation of magnetism reported experimentally, which has been beyond theoretical expectation and unsolved for 14 years. It proposes a new condition on materials based on "topology", which will accelerate the material development for spintronics and will contribute to further reduction of power consumption in "electric manipulation of magnetism" toward application for magnetic memories.
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Precise measurement of the Σ-proton elestic scattering at the J-PARC

YAMAMOTO Takeshi
R.G.for Hadron nuclear physics

International research group including Takeshi Yamamoto (Advanced Science Research Center, Japan Atomic Energy Agency) has developed a method to investigate "extended nuclear force" through a measurement of elastic scattering between protons and Σ particles, which include strange quark.
A cross section of the Σp scattering was successfully measured with new experimental technique to overcome a difficulty due to a short lifetime of Σ particle. Study of "extended nuclear force" will be promoted with further experimental data of scatterings between protons and various "strange" particles with newly developed experimental method.
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Split second behavior of muons in atoms uncovered for first time

HASHIMOTO Tadashi
R.G.for Hadron nuclear physics

International research group including Tadashi Hashimoto (Advanced Science Research Center, Japan Atomic Energy Agency) clarified the dynamics of the muonic atom formation process, a phenomenon that is overs in a few tens of femotoseconds.
In an experiment perfomed at J-PARC MLF, electronic characteristic X-rays emitted by muonic atoms during deexcitation were measured using a state-of-art cryogenic X-ray detector called a transition-edge-sensor microcalrimeter (TES). An excellent energy resolution of the TES detecotor revealed assymetric shapes of the electric K lines from muonic iron atoms for the first time. Assitsted by a cascade simulation, these data clarified how the muon moves and how the electron configurations and numbers change accordingly during the muon cascade process. This result greatly contributes to the development of new research fields including the dynamics of exotic quantum few-body systems such as muonic atoms.
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Chemical Characterization of a Volatile Dubnium Compound, DbOCl3

SATO Tetsuya
R.G.for Heavy element nuclear science

Research Group for Heavy Element Nuclear Science has successfully synthesized and separated single atoms of dubnium （Db, element 105） in the form of its volatile oxychloride.
Based on comparative studies with the lighter homologs of Group 5 in the Periodic Table clearly indicated that Db compounds would more volatile than that expected from the homologs. From the obtained experimental results, thermochemical data for Db compounds are derived. The present study delivers a better understanding of the properties of elements in the extreme region of the Periodic Table.
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A new spintronic phenomenon, chiral-spin rotation, found in non ―collinear antiferromagnet―

IEDA Jun'ichi
R.G.for Spin-energy transformation Science

A joint research team of Tohoku University and Japan Atomic Energy Agency found a new spintronic phenomenon, a persistent rotation of chiral-spin structure, that has no parallel in the research history of electrical control of magnetism.
The response of the chiral-spin structure of a non-collinear antiferromagnet Mn3Sn thin film to electron spin injection shows persistent rotation at zero magnetic fields, whose frequency can be tuned by the applied current. The phenomenon shown here provides a very efficient scheme to manipulate the magnetic structure, offering new opportunities for applications.
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Cooling to absolute zero by magnets―"Ytterbium magnetic material" extreme low temperature coolant with micro magnets fructuating quantum mechanically―

TOKIWA Yoshifumi
R. G. for Material Physics in Heavy Element Systems

Ytterbium magnetic material, which has a strong quantum effect, has been shown to be an excellent magnetic coolant that can reach extremely low temperatures near absolute zero, by Yoshifumi Tokiwa Senior Scientist of the Materials Physics for Heavy Element Systems Research Group, Advanced Science Research Center. Currently, it has been concerned that the mainstream helium refrigerators rely on the helium-3 gas, which is extremely rare and the supply is unstable because it is produced only in nuclear reactors or in the process of pruduction of nuclear weapons.
On the other hand, the raw material for ytterbium magnetic material is easily available. With the advent of this high-performance coolant, it is expected that magnetic cooling using ytterbium magnetic material will replace the current cooling method and be widely used in quantum computers and the like.
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"Power Spintronics", a little giant? Toward miniaturization of power supply circuits and utilization of “negative inductance”, the trump card for noise elimination ?

IEDA Jun'ichi
R.G.for Spin-energy transformation Science

A new method controlling an "inductance" of electronic circuits in a wide range has been found based on spintronics phenomena.
The findings stimulate research for "miniaturization of power supply circuits" and "electromagnetic noise reduction" using negative inductance, which will ultimately determine the size and weight of electronic devices. This achievement will open up a new technological field of "power spintronics," in which electric power is controlled via spin, and is expected to contribute to the innovation of power supplies based on quantum technology in the future.
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The first determination of the Xi hypernuclear mass.New insights toward understanding of the origin of nuclei and structure of neutron stars.

HAYAKAWA Shuhei
R.G.for Hadron nuclear physics

An international team of J-PARC E07 experiment observed the decay of a Xi hypernucleus in a nuclear-emulsion experiment carried out at J-PARC, Tokai, Japan.
In the observed event, which is named “IBUKI” after Ibuki Mountain in Gifu, a Xi-minus particle1), which contains two strange quarks, was bound to a Nitrogen-14 nucleus. By a detailed analysis of the decay products observed in the emulsion, the Xi hypernucleus mass could be precisely determined for the first time. The precise mass measurement of Xi hypernuclei gives information on “strong interaction” between a Xi-minus particle and a nucleus, and underlying interaction between a Xi particle and a proton/neutron. Since particles containing strange quark (hyperons), such as a Xi-minus particle, are predicted to appear in the core of neutron stars, which are the densest objects in the Universe, then the strength of the interaction leads to an understanding of which hyperons appear in which densities in neutron stars, and hence the structure like the radius and pressure inside. This result, therefore, is expected to contribute the understanding how the matter was formed from quarks, the elementary particles, and what is the structure of interior of neutron stars which are often described as giant nuclei.
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Carbonated apatite nanocrystal derived from bone waste for the removal of toxic ions

Sekine　YurinaR.G.for Interfacial reaction-field chemistry

Remediating toxic ion contamination is crucial for protecting human health and the environment.
This study aimed to provide a powerful strategy for effectively utilizing bone waste from the food production and preparation industries for removal of toxic ions. Here, we show that immersing pig bone in NaHCO3 aqueous solution produced a carbonated nanohydroxyapatites (C-NHAP). The C-NHAP exhibited high adsorptivity for Sr2+, Cd2+, Pb2+, and Cu2+. The strontium adsorptivity was about 250 and 4,500 times higher than that of normal bone and synthetic HAP, respectively. The C-NHAP is an eco-friendly, high-performance material that is simple to prepare and should be useful for tackling problems of food waste disposal and environmental pollution.
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Discovery of alpha particles on tin isotopes
- new insight into neutron star structure and alpha decay -

Kazuki YoshidaR.G.for Advanced Theoretical Physics

International collaboration research including Kazuki Yoshida (Advanced Science Research Center, Japan Atomic Energy Agency) has discovered alpha particles (4He nucleus consisting of 2 protons and 2 neutrons) on the surface of tin (Sn) isotopes.
The experiment was performed at the nuclear experimental facility in the Research Center for Nuclear Physics (RCNP), Osaka University. The result has a huge impact on our knowledge of neutron stars and the mechanism of the alpha decay. Only a theoretical study predicted the alpha particles on the surface of heavy nuclei before this experiment. A proton beam was accelerated up to 400 MeV (million electron volt) by the RCNP cyclotron and bombarded on tin isotopes (112Sn, 116Sn, 120Sn, 124Sn). The existence of the alpha particles was confirmed by analyzing emitted protons and knocked out alpha particles from the tin target.
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How many neutrons can exist in nuclei?

Yutaka UtsunoR.G.for Advanced Theoretical Physics

A new principle for determining the maximum number of neutrons in a given isotope chain is found by a research group that includes a scientist from the ASRC.
A first-principles nuclear-structure calculation making a full use of supercomputers points to a crucial role of binding energy that is changing with the neutron number due to nuclear shape transition. Despite very short β-decay lifetimes, nuclei with a very large neutron number are created on the way of nucleosynthesis, and the present finding could greatly contribute to clarifying the origin of elements on earth.
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Eco-friendly carboxymethyl cellulose nanofiber hydrogels prepared via freeze crosslinking and their applications

Yurina SekineR.G.for Interfacial reaction-field chemistry

A research team led by Dr. Yurina Sekine at the Advanced Science Research Center and the Materials Sciences Research Center has developed a crosslinking method using freeze-concentration and used it to synthesize a new type of carboxymethyl cellulose nanofiber (CMCF) hydrogel with high water content, high compressive strength, and high compressive recoverability.
The hydrogels were prepared by adding an aqueous solution of citric acid to a frozen CMCF and then thawing the sol. This gelling process is called freeze crosslinking. The physically crosslinked CMCF hydrogels are non-toxic, metal-free, and simple to prepare, and thus they may be useful as sustainable materials in various fields.
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Tolerance of spin-Seebeck thermoelectricity against irradiation by swift heavy ions

Satoru OkayasuR.G.for Spin-energy transformation Science

A research team led by Senior Scientists Satoru Okayasu and Jun’ichi Ieda at the Advanced Science Research Center has demonstrated that a "spin thermoelectric (STE) device", which generates electricity from heat, has a very high radiation tolerance.
Recently, STE devices relying on electron spins have been developed, and are expected to outperform existing technologies in terms of flexibility in design, low environmental impact, and economic efficiency. However, it has not yet been confirmed whether the device's performance can be maintained in the harsh environment where radioisotopes coexist. To address this, in this study, the service life of the device was estimated by irradiating it with heavy ions, and it was confirmed that the performance of the device would not deteriorate for several hundred years even if spent nuclear fuel was used as a heat source. In the future, it is expected to contribute to the development of new technologies for the safe and effective utilization of waste heat from spent nuclear fuels in the radiation environment.
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One-way traffic of surface acoustic waves across a magnetic barrier

Kei YamamotoR.G.for Spin-energy transformation Science

A new study by researchers from Riken Center for Emergent Matter Science, Japan Atomic Energy Agency, Institute for Solid State Physics (U. of Tokyo), Ecole Polytechnique Federale de Lausanne, and Hitachi Ltd. shows that when surface acoustic waves propagate past a thin magnetic film, there is a large difference in the absorption of the waves by the magnet depending on whether the waves are incident from the right or left side of the film.
Although such a rectification effect of magnets has been known, the previous studies suggested that the effect was generally small, and would become weaker for thinner films that are likely to be used in potential applications. The new experimental data indicates a complete disappearance of absorption for an incident wave from one side while maintaining a strong absorption for the other in an ultra-thin magnetic film of 1.6 nm (a billionth of a meter), which imples a 100% efficiency of the rectification effect. The discovery could prove to be a promising way forward in the pursuit of insulator-based communications devices by offering a rectification function for acoustic waves, which acts analogously to a diode for electronic circuits.
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New research deepens mystery of particle generation in proton collisions

Kiyoshi TanidaR.G.for Hadron nuclear physics

A group of researchers including scientists from the Japan Atomic Energy Agency (JAEA) used the spin-polarized Relativistic Heavy Ion Collider (RHIC) at Brookhaven National　Laboratory in the United States to show that, in polarized proton-proton collisions, neutral pions emitted in the very forward area of collisions?
where direct interactions involving quarks and gluons are not applicable?still have a large degree of left-right asymmetry. This finding suggests that the previous consensus regarding the generation of particles in such collisions needs to be reevaluated.
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Significant improvement in power generation efficiency of hydrodynamic power generation via spin current
- pave the way for new nanofluidic devices applying spintronics -

Hiroyuki ChudoR.G.for Spin-energy transformation Sciences

H. Chudo (deputy chief researcher, JAEA), R. Takahashi (Assistant Professor, Ochanomizu University (at the time of research, post-doctoral researcher, JAEA)), M. Matsuo(Associate Professor, Chinese Academy of Sciences (at the time of research, deputy chief researcher, JAEA)), S. Maekawa, (Senior Researcher, RIKEN (at the time of research, director of ASRC, JAEA)), E. Saito, (Professor, the University of Tokyo), et al, elucidate the mechanism of the hydrodynamic power generation via a spin current in a channel with a micro meter order, and discovere the efficiency of power gneration significantly enhances with smaller size of the channnel.
The flow in a fine channel becomes a laminar flow, and liquid movement like a vortex is widely distributed throughout the channel. This leads to more suitable characteristics for miniaturization and increased power generation efficiency. The basic theory of fluid power generation via spin current was predicted by M. Matsuo in 2017. In this research, we have experimentally demonstrated that the power generation efficiency was improved about 100,000 times in the laminar flow region. The results of this research indicate that the fluid power generation via the spin current will be greatly improved by miniaturization. In addition, no additional equipment is required inside or outside the flow cannel. Therefore, it is expected to be applicable to nanofluidic devices and flow meters for minute flow.
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Electrons make a deal with the devil
- A forty-year mistery in magnetic material -

Yoshinori HagaR.G.for Material Physics in Heavy Element Systems

The JAEA, in collaboration with the University of Tokyo and RIKEN, has clarified the peculiar behavior of conduction electrons in exchange for accepting a strongly correlated state in the complex phase transition phenomenon of Cerium-Antimony (CeSb) called "devil's staircase".
This research group investigated the mechanism that induces the "devil's staircase" by measuring spin arrangements and conduction electrons using ultra-high resolution laser photoelectron spectroscopy. As a result, it is shown that conduction electrons, which are supposed to move freely, form a pseudo-gap state to obtain energy gain and eventually causes the "devil's staircase". The strong correlation between electrons and spins clarified in this study can potentially be applied to spintronics magnetic material design, because conduction electrons are controlled by the spin arrangement to function as the operating principle of devices like magnetic memories.
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Structure of superconducting Ca-intercalated bilayer Graphene/SiC studied using total-reflection high-energy positron diffraction

Yuki FukayaR.G.for Nanoscale Structure and Function of Advanced Materials

We have investigated the atomic structure of superconducting Ca-intercalated bilayer graphene on a SiC (0001) substrate using total-reflection high-energy positron diffraction. By comparing the experimental rocking-curves with ones calculated for various structural models using a full-dynamical theory, we have found that Ca atoms are intercalated in the graphene-buffer interlayer, rather than between the two graphene layers.
From transport measurements, the superconducting transition was observed to be at Tconset = 4 K for this structure. This study is the first to clearly identify the relation between the atomic arrangement and superconductivity in Ca-intercalated bilayer graphene.
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Spin Seebeck mechanical force

Kazuya HariiR.G.for Spin-energy transformation Science

Electric current has been used to send electricity to far distant places. On the other hand, spin current, a flow of electron spin, can in principle also send angular momentum to distant places.
In a magnet, there is a universal spin carrier called a spin wave, a wave-type excitation of magnetization. Since spin waves exhibit a long propagation length, it should be able to send angular momentum that can generate torque and force at a distant place: a new function of magnets. Here we observe mechanical angular momentum transmission and force generation due to spin waves injected into Y3Fe5O12 by the spin-Seebeck effect. The spin-wave current, transmitted through a Y3Fe5O12 micro cantilever, was found to create a mechanical force on the cantilever as a non-local reaction of the spin-Seebeck effect. Spin-wave current can be generated remotely even in open circuits, and it can be used to drive micro mechanical devices.
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Topological Characterization of Classical Waves: The Topological Origin of Magnetostatic Surface Spin Waves

Kei YamamotoR.G.for Spin-energy transformation Science

We propose a topological characterization of Hamiltonians describing classical waves. Applying it to the magnetostatic surface spin waves that are important in spintronics applications, we settle the speculation over their topological origin. For a class of classical systems that includes spin waves driven by dipole-dipole interactions, we show that the topology is characterized by vortex lines in the Brillouin zone in such a way that the symplectic structure of Hamiltonian mechanics plays an essential role.
We define winding numbers around these vortex lines and identify them to be the bulk topological invariants for a class of semimetals. Exploiting the bulk-edge correspondence appropriately reformulated for these classical waves, we predict that surface modes appear but not in a gap of the bulk frequency spectrum. This feature, consistent with the magnetostatic surface spin waves, indicates a broader realm of topological phases of matter beyond spectrally gapped ones.
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Observation of a Be double-Lambda hypernucleus in an experiment at J-PARC

Junya YoshidaHadron nuclear physics

An international research team led by JAEA, Gifu University, J-PARC center, and KEK has detected a new hypernucleus of Bellilium having additional two Lambda particles, so-called "double Lambda hypernucleus (DLH)".
One of the goals of modern physics is to understand the mechanism of matter formation through the hierarchical structure from quarks to nuclei. The studies of hypernuclei are essential issues because they extend our knowledge of the ordinary nucleus to the more general nucleus having strange-quark. Particularly, systematic studies of various DLHs are important and challenging issues. We performed an experiment named E07 at J-PARC. It was designed to detect 100 times higher statistics of DLH compared to past experiments with the high-intensity beam of J-PARC. In this experiment, we detected the 2nd identified DLH event named "MINO" and measured its mass. We reconstructed the Lambda-Lambda interaction from the mass. The strength of the interaction was different from that of the 1st identified DLH, so-called "NAGARA". This result is the 1st example that Lambda-Lambda interaction has changed due to the nuclear structure. We will continue the search for new DLHs. DLHs are recorded in photographic emulsion sheets and searched under optical microscopes with automated image recognition. We expect to detect several more new DLHs within a few years. Furthermore, we intend to accelerate the DLH hunting with a new technique, so-called the "Overall scanning method". This result may lead to the understanding of the internal state of neutron stars. Many scientists predict Lambda particles should appear spontaneously in neutron stars by nuclear processes in the high-pressure environment. This result shall be used to validate the scenarios.
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Control the high speed motion of "magnetic wall" with voltage
- pave a way for high performance magnetic memory -

Jun'ichi IedaR.G.for Spin-energy transformation Science

Researchers in U. Tokyo, UEC, and JAEA succeeded in the controlling the high speed motion of a magnetic domain wall (DW) by voltage application.
The technology to drive the DW at a higher speed is indispensable for improving the performance of the magnetic memory. To this end, applying voltages to the magnet is a promissing method with high energy efficiency but previous reports were limited to the extremely slow speed operation of 1 mm/sec or less. In this research, it was demonstrated that the DW speed in the region exceeding 100 m/sec is shifted by the voltage. The success in a practical speed region for a memory device is the first time and it opens a way to realize a "race track memory" expected as the ultimate storage memory with high speed, large capacity, high durability.
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Superconductivity and magnetic fluctuations
-Strong correlation between ferromagnetic fluctuations and pressure-induced superconductivity-

Naoyuki TateiwaResearch Group for Heavy Element Materials Physics

We find the strong correlation between ferromagnetic fluctuations and pressure-induced superconductivity in uranium ferromagnetic superconductor UGe2.
It has considered that the ferromagnetism and the superconductivity compete with each other. However, the coexistence of both phases has been discovered in several uranium compound. We show that the ferromagnetic fluctuations enhanced under high pressure may take an important role for the superconductivity. We hope that this study contributes to further developments for a complete understanding of the superconductivity.
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Observation of disappearance of angular momentum of electron in magnet by rotating the magnet at high speed
-Toward searching for materials for high-speed magnetic devices with the disappearance of angular momentum-

Masaki IMAIR.G.for Spin-energy transformation Science

Researchers in JAEA and RIKEN have developed a versatile angular momentum measuring apparatus to observe the temperature dependent spin of electrons (angular momentum) by rotating the sample at high speed.
Moreover, they investigated the magnitude of angular momentum using this apparatus, and observed that the angular momentum disappears with a specific magnetic material. The magnetic reversal process and the angular momentum are closely related, and the magnetic reversal speed is accelerated when the angular momentum is small. By measuring the angular momentum of various materials with this apparatus, it is expected to search for materials for the next generation high speed magnetic devices.
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Giant Faraday rotation in metal-fluoride nano-granular films
- Discovery of the magneto-optical effect dreamed since 1972 -

Sadamichi MAEKAWABo GU(Spin-energy Transformation Science)

JAEA has discovered a new magneto-optical material, (Fe,FeCo)-(Al-, Y-fluoride) nano-granular films exhibiting giant Faraday effect, 40 times larger than that of Bi-YIG, which has been used for optical communications since 1972.
These newly discovered material will contribute greatly to the miniaturization and integration of optical devices.
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The Advanced Science Research Center

Every March, the American Physical Society (APS) produces a number of short movies showcasing world-leading international research institutes.
The Advanced Science Research Center (ASRC) at JAEA was selected as one of the institutes to be portrayed in 2018. The video on ASRC was released in March.
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Superconductivity surviving in high magnetic field
-Clarifying the mechanism of the superconductivity which can survive in high magnetic field appeared in uranium compound -

Taisuke HATTORIMaterials Physics for Havy Element Systems

JAEA has succeeded to clarify the mechanism of superconductivity in uranium compound URu2Si2 using JAEA facility; why the superconductivity of this compound can survive under the extremely high magnetic field.
So far, experimental resolusion has not been enough due to the difficulty of treating the nuclear fuel material. This result can lead development of more useful superconducting magnet.
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Spin Current Noise of the Spin Seebeck Effect and Spin Pumping
-A new method toward high efficiency spin current generation-

Yuichi OHNUMA, Sadamichi MAEKAWASpin-energy transformation Science

A theory of spin current noise has been constructed in a normal-metal/ ferromagnet bilayer systems.
The theory is applied to estimate heat in the spin pumping by micro-waves. It may also be used to obtain high efficiency spin current generation technology.
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Surprising Result Shocks Scientists Studying Spin
- Findings on how differently sized nuclei respond to spin offer new insight into mechanisms affecting particle production in proton-ion collisions at the Relativistic Heavy Ion Collider (RHIC)-

Kiyoshi TANIDAHadron nuclear physics

Scientists at Japan Atomic Energy Agency, RIKEN, and Brookhaven National Laboratory shocked by results of spinning protons striking different sized atomic nuclei at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory.
Neutrons produced when a spinning proton collides with another proton come out with a slight rightward-skew preference.
But when the spinning proton collides with a much larger gold nucleus, the neutrons' directional preference becomes larger and switches to the left.
The scientists will execute a new series of experiments colliding polarized protons with other kinds of nuclei to study the electromagnetic interaction effect.
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Direct observation of orbital ordering using scanning tunneling microscopy
- Novel phenomena realized at the surface of matter -

Yoshinori HAGAMaterials Physics for Heavy Element Systems

ISSP, University of Tokyo and JAEA have found an ordering of electron orbitals at the surface of a heavy fermion superconductor CeCoIn5.
By using the highly stabilized scanning tunneling microscopy, they succeeded to directly observe the orbital ordering in real space for the first time.

Spin current generation in Cu by acoustic wave injection
- towards magnetic devices without rare metals and magnet -

Mamoru MATSUO etcSpin-energy Transformation Science

Keio University, Tohoku University, and JAEA succeded in generating "spin current", the flow of magnets by injecting Rayleigh wave into copper.
This result is expected to make a significant contribution as a high performance, power saving, and inexpensive rare metal free technology of magnetic devices, which are widely installed in portable information terminals such as smart phones.
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Experiments using einsteinium isotope, element 99
- First experiments under the Japan-US collaboration -

Katsuhisa NISHIO etcHeavy Element Nuclear Science

JAEA will obtain einsteinium isotope 254Es (element 99) from Oak Ridge National Laboratory (ORNL).
Using the experiemntal setups developed by JAEA in the tandem facility and the SPring-8, experiments such as fission mechanism and hydration structure are planned.

One-dimensional spinon spin currents

Sadamichi Maekawa etc

Spinons behave as a Tomonaga?Luttinger liquid at low energy, and the spin system is often called a quantum spin chain.
Here we show that a quantum spin chain generates and carries spin current, which is attributed to spinon spin current.
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Optically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance

Sadamichi Maekawa etc

Developing optically transparent magnets at room temperature is an important challenge.
They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region.
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Symmetry breaking in atomic coordinates of germanene

Yuki Fukaya etcResearch Group for Nanoscale Structure and Function of Advanced Materials

We have determined the structure of germanene, germanium version of graphene, on an aluminum substrate using total-reflection high-energy positron diffraction (TRHEPD) method.
The present study revealed that germanene has an asymmetric structure.
More details are shown here.

Establishing a new method to take nuclear fission data
- Opening a new region for fission research -

Katsuhisa Nishio etcResearch Group for Heavy Element Nuclear Science

A new method to obtain fission fragment mass distributions using multi-nucleon transfer reactions was established, which generates data for more than fourteen nuclei at once including neutron-rich nuclei not investigated so far.
A fluctuation-dissipation model successfuly explains the measured data.
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New technology for migration control of cesium from forests to living area. Regeneration of village forests by using natural force with polymers and clay. Evolving verification tests in Iitate village, etc., Fukushima. Expectation for prevention of recontamination of living area.

Hirochika Naganawa etcResearch Group for Interfacial reaction-field chemistry

In order to gently regenerate village forests without destroying forest ecosystem, a new technology for migration control of radioactive cesium has been developed.
By scattering bentonite that adsorbs cesium on slope grounds covered by leaf soil, the uptake of cesium to plants is suppressed. The bentonite adsorbing cesium is transferred by rainwater flow and then captured by interpolyelectrolyte complex (self-assembly of polyelectrolytes having opposite charge by electrostatic interaction).
Patent-pending

Large-scale nuclear-structure calculation for constraining the masses of neutrinos using the K supercomputer

Yutaka Utsuno etcResearch Group for Heavy Element Nuclear Science

On the basis of large-scale nuclear-structure calculations using the K supercomputer, the most reliable value of the nuclear matrix element for neutrinoless ββ decay in Ca-48 is provided by a collaboration group among the University of Tokyo, Japan Atomic Energy Agency, and other institutes.
This data will strongly narrow the range of neutrino masses when the neutrinoless ββ decay in Ca-48 is observed.
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Interface structure between graphene and metal substrate revealed by total-reflection high-energy positron diffraction (TRHEPD)

Yuki Fukaya etcResearch Group for Nanoscale Structure and Function of Advanced Materials

Collaborative research team of JAEA and KEK experimentally verified using total-reflection high-energy positron diffraction (TRHEPD) that the spacing between graphene and metal substrate depends on the substrate material.
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Surface structure determination of TiO2 photocatalyst using total-reflection high-energy positron diffraction (TRHEPD)

Yuki Fukaya etcResearch Group for Nanoscale Structure and Function of Advanced Materials

Collaborative research team of KEK, Hokkaido University, and JAEA experimentally determined the surface structure of TiO2 photocatalyst using total-reflection high-energy positron diffraction (TRHEPD)
More details are shown here.

Our research got featured in News&Views of Nature Physics and Nature Materials.

Spin-energy Transformation Science

Our latest research achievement "Electrical generation from quantum mechanical spinning motion in a liquid metal", press released on November 03, 2015, was featured in News&Views of Nature Physics and Nature Materials.
Nature Materials
Nature Physics

Nuclear charge symmetry breaking by a "strange particle" observed at J-PARC Hadron Experimental Facility

Hiroyuki SAKO etcResearch Group for Hadron Nuclear Physics

An international collaboration led by Tohoku University, High Energy Accelerator Research Organization (KEK), and Japan Atomic Energy Agency (JAEA) found fundamental symmetry called "charge symmetry" is broken by adding a "strange" particle, Lambda, to a nucleus in an experiment at J-PARC Hadron Experimental Facility.
More details are shown here.

Strong Suppression of the Spin Hall Effect in the Spin Glass State

Sadamichi MAEKAWA etc

In spin glass metals, where localized moments are polarized in random directions, the relative dynamics between the localized moment and the conduction electron spin is successfully probed by the spin Hall effect.
Such spin dynamics is very difficult to be detected even by the superconducting quantum interference device (SQUID), the most sensitive magnetometer at the present stage. Such technique can be applied to develop the highly sensitive magnetic sensors.
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Electrical generation from quantum mechanical spinning motion in a liquid metal

Mamoru MATSUO etcSpin-energy Transformation Science

The team found a new method of power generation by using electron spinning motion in a liquid metal via the quantum mechanical coupling between electron and fluid vorticity.
The result can be used as an electric generator and a spin generator in, e.g., micro-electromechanical system free from magnetic fields.
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Development of synthesis process of novel composite nanotubes using ion irradiation technique

Hidehito Asaoka etcResearch Coordination and Promotion Office

We have succeeded the development of synthesis process of novel composite nanotubes, which are consisted of different crystal states or new microstructures, using ion irradiation technique.
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Observation of giant spin-Hall effect mediated by quasiparticles in a superconductor

Sadamichi Maekawa etcResearch Group for Spin-Energy Transformation Science

・First demonstration of the spin-Hall effect in a superconductor.
・More than 2000 times enhancement of the effect has been achieved compared to the normal conductor case. ・This finding opens the door to next-generation spintronics devices such as a "spin-meter" that magnifies and detects tiny spin signals.
More details are shown here.

Novel mechanism of superconductivity induced by strong magnetic field

Yo TOKUNAGAR.G. for Materials Physics for Heavy Element Systems

Reentrant superconducitivity has been discovered in uranium based compound URhG under strong magnetic fields. We have revealed the noevel mechansim of this exotic phenomenon by means of Nuclear Magnetic Resonance (NMR) technique.
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Measurement of the first ionization potential of lawrencium (element 103) - Unravelling Relativistic Effects in the Heaviest Actinide Element -

Tetsuya　K. Sato et al.R.G. of Heavy Element Nuclear Science

We report that the experimentally obtained the first ionization potencial of the heaviest actinide, lawrencium (Lr, atomic number 103), is 4.96 eV.
The value was measured with Lr-256 (half-life 27 seconds) using an efficient surface ion-source and a radioisotope detection system coupled to a mass separator at the JAEA tandem accelerator. The measured ionization potencial is in excellent agreement with the value predicted here by state-of-the-art relativistic calculations.
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The Newest Nuclear Decay Data in Hands ? Completion of a comprehensive portable nuclear decay data map, “JAEA Chart of the Nuclides 2014” ?

Hiroyuki KOURA etcR.G. for Reactions Involving Heavy Nuclei

We have constructed a folding (A4-size) nuclear chart, “JAEA Chart of the Nuclides 2014,” including the latest experimental (3,150 points) and theoretical (1,578 points) decay data for nuclear science experts and the general public.

Discovery of a novel principle of generating spin currents from insulators under light illumination

Sadamichi MAEKAWA etcResearch Group for Condensed Matter Theory

A conversion of light energy into spin currents in magnetic insulators is demonstrated for the first time with the aid of "surface plasmon", a collective excitation of electrons in metal nanoparticles under light illumination.
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Transformation between electric- and spin-currents in metals

Sadamichi MAEKAWA etcResearch Group for Condensed Matter Theory

We have theoretically shown that electron-electron correlation is necessary to reproduce the experimental results of the spin Hall effect in Ir-doped Cu.
More details are shown here.

Change of heat current by magnetic field: Possibility of heat control by magnet

Sadamichi MAEKAWA etcResearch Group for Condensed Matter Theory

Concerning the phonon Hall effect, it has not been clarified the mechanism why a heat current is changed by a magnetic field.
We theoretically show that this effect is due to resonant skew scattering of phonons from a tiny amout of magentic impurities.
More details are shown here.

Observation of colossal thermomagnetic response due to superconducting fluctuation

Yoshinori HAGA etcR.G. for Actinide Materials Science

Thermomagnetic effect was investigated on an ultra-clean single crystal of a uranium superconductor URu2Si2. Colossal thermomagnetic response a million times larger than the theoretical prediction has successfully been detected.
This observation proofs the superconducting fluctuation in this material.
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Efficient method developed for radioactive cesium recovery from sewage sludge ashes

Naofumi Kozai etcResearch Group for Bioactinideｓ　Chemistry

We have revealed the chemical states of radioactive cesium in the sewage sludge ashes produced after the Fukushima Daiichi nuclear power plant accident and have succeeded in recovering more than 90 % of radioactive cesium in the ashes by pre-pulverizing the ashes to particles less than 1 μm and heating them in acid solutions.
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Mottled electrons condensation induced by magnetic field. -Development of heavy element new materials controlled by magnetic field-

Shinsaku KAMBE etcR.G. for condensed matter physics of heavy element systems

Mottled electronic state is found in an Yb-based compound around a magnetic field induced quantum critical phase transition at low temperatures.
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Succesfully synthesis and detection of a Seaborgium (element 106) carbonyl complex - Seaborgium shows a typical chemical property of the group six in the periodic table of the elements -

Masato Asai etcResearch Group for the Superheavy Elements

For the first time, a chemical bond was established between a superheavy element ? seaborgium (element 106) in the present study ?
and a carbon atom by an international collaboration with research groups from Univ. Mainz, GSI and RIKEN. Seaborgium were converted into seaborgium hexacarbonyl complexes. Its gaseous properties and adsorption to a silicon dioxide surface were studied, and compared with similar compounds of neighbors of seaborgium in the same group of the periodic table.
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Development of a Novel Spectroscopic Technique to Observe Synergy Effect of Water with Radiation in the DNA Damage Processes

Akinari Yokoya, Ph.D. etcResearch Group for Radiation and Biomolecular Science

We have developed an novel spectroscopic technique, using high brilliant X-rays provided by SPring-8, to study synergy effect of radiation and water on the processes of DNA damage induced by radiation.
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Succses in developing a nanoglanuler material that shows giant dielectric and magnetoelectric responses at room temperature - Creation of a new multifanctional material -

Sadamichi MAEKAWA etc

The newly developmed material is a thin-film dielectric material consists of metal and insulator phases, in which nano-magnetic particles have been dispersed in a inslator matrix.
This so-called nanogranular material shows giant dielectric and magnetoelectric responses at room temperature.
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New phenomenon of magnetism in uranium ferromagnetic superconductors : To solve the mechanism for the co-existence of the magnetism and superconductivity

Naoyuki Tateiwa etcResearch group for actinide material science

We have found new phenomenon of magnetism in uranium ferromagnetic superconductors UGe2 and URhGe where the ferromagnetism and superconductivity co-exist.
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Direct observation of the 'hidden order': a longstanding mystery in solid state physics

Yoshinori HAGA etcR.G. for Actinide Material Science

Deformation of the crystal lattice was detected in the hidden-order phase of URu2Si2 by using an ultra high-resolution crystallography with synchrotron radiation at SPring-8.
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Nuclear magnetic resonance study of uranium compound URu2Si2 by the world's strongest magnetic field

Hironori Sakai etcResearch Group for Condensed Matter Physics of Heavy Element Systems

An unknown magnetic structure in uranium compound URu2Si2 induced by high field over 35 tesla, has been determined by means of nuclear magnetic resonance technique.
The experiment was performed using the world's strongest magnetic field in National High Magnetic Field Laboratory (NHMFL) in Tallahasee, USA.
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New human eyes for seeing thorough materials -Development on non-destructive light elemental analysis for extraterrestrial materials using a muon beam-

Wataru Higemoto etcR.G. for condensed matter physics of heavy element systems

By using the most intense pulsed muon beam at J-PARC MUSE(MUon Science Establishment), we successfully demonstrate a depth-profile analysis of light elements (B, C, N, and O) from several mm-thick layered materials and non-destructive bulk analyses of meteorites containing organic materials.
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Success in observation of nucler spin controled by rotation

Hiroyuki CHUDO etcR.G. for Spin Manipulation and Material Design by Combining Spintronics and High-Speed Rotation Technique

We have developed a unique conceptual measurement system of nucler spin of materials in rotoational speed of 10000 times per 1second based on nuclear magnetic resonance method.
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Total reflection positron diffraction and its applications to surface study

Atsuo Kawasuso etcGroup Leader of spin-polarized positon beam research group

2014, Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology
Kawasuso, Group Leader, and his colaborators received the above award.

Improvement of total reflection positron diffraction realized ultimate surface structure analysis

Atsuo Kawasuso etcSpin-polarized positon beam research group

We improved the total reflection positron diffraction method by enhancing the brightness of positron beam at KEK slow positon facility.
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DNA damage affects normal chromosomes in a living cell - A step in advance for the radiobiologicall effect-

Ayumi Urushibara, Ph.D. etcPost doctrral fellow of JAEA (Present position: Visiting Scientist of Osaka prefecture Univ.)

We found that radiation damage to DNA could affect non-irradiated normal chromosomes to induce genetic instability. This project has been perfomed by collaboration with Prof. Seiji Kodama in Osaka prefectrue univ. (Pregident:Taketoshi Okuno)
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20th gold medal prize, "discovery of electric spin curent fandamentals"

This prize is one of the prestigious prize in Science for Japanese scientist. Yomiuri Tchno Forum selects luminary scientists 3 or so per a year.
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