CMRC

KEK

Project

Quantum-beam studies on dynamical cross-correlated physics in strongly-correlated-electron systems

Project Leader: Hajime SAGAYAMA

Under Construction

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Controlling of physical properties in molecular systems

Project Leader: Reiji KUMAI

In this project, electronic correlation in molecular crystal systems is being investigated to elucidate novel phenomena such as superconductivity, ferroelectricity and charge ordering. One of our goals is to elucidate the origins of physical properties from information on the crystal structure, and so we have performed crystal structure analysis of various molecular systems including organic thin films under external conditions.
In the first period of the CMRC, we did a lot of work on the structural study of organic ferroelectrics. Recently we have succeeded in making a high-quality thin film of organic ferroelectric and evaluated it by using the diffraction of synchrotron radiation as described below.
In addition, we started the commissioning of the thin film diffractometer installed in BL-7C, Photon Factory, KEK. This will accelerate the structural investigation of thin films.

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Observation and control of novel quantum phenomena in superstructures of strongly-correlated oxides

Project Leader: Hiroshi KUMIGASHIRA

The goal of this project is to design novel physical properties appearing at the heterointerface of strongly correlated oxides. The physical properties arise from strong mutual coupling among the spin, charge, and orbital degrees of freedom in the interface region between two different oxides. In order to control such properties, it is necessary to clarify the interfacial electronic, magnetic, and orbital structures. We are therefore using synchrotron radiation spectroscopic techniques having elemental selectivity to probe these structures in the nm-scale at the oxide heterointerface. For example, the electronic structure at the interface is determined by photoemission spectroscopy (PES) and X-ray absorption spectroscopy (XAS), the magnetic structure by magnetic circular dichroism of XAS, and the orbital structure by linear dichroism of XAS. We aim to design and create novel quantum materials by optimally combining sophisticated oxide growth techniques using laser molecular beam epitaxy (MBE) and advanced analysis techniques using quantum beams.

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Emerging phenomena induced by deformation of local structure in strongly correlated electron system

Project Leader: Masaki FUJITA

Under Construction

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P-V-T-dε/dt Materials Structure Science

Project Leader: Nobumasa FUNAMORI

Both static- and shock-compression experiments have a long history, and have been closely related to each other. For instance, Hugoniot compression curves measured under shock compression have been used as a pressure scale in static-compression studies. However, significantly different phenomena have been often observed in the two types of experiments for the same samples, and therefore some researchers consider that it makes no sense to compare them. For example, increases in electrical conductivity of some insulators observed under shock compression have not been observed under static compression and some phase transitions observed under static compression have not been observed in recovered samples after shock compression. These discrepancies are likely due to a large difference in strain rate during compression: 10−6-10−1s−1 during static compression and 106-109 s−1 during shock compression. There has not yet been enough cooperation among researchers engaged in static- and shock-compression experiments and the relation between the strain rate and the changes in structure and properties is not understood sufficiently.
Synchrotron X-ray techniques are powerful tools for studying the effect of strain rate on the behavior of materials. High-pressure synchrotron XRD under static compression has yielded many important results and significantly contributed to the development of high-pressure science since the 1980s. On the other hand, shock-compression experiments with synchrotron X-rays are still in an early phase of development. There is an urgent need to develop time-resolved XRD with a shockwave driven laser pulse.
In this project, we have gathered a group of researchers specialized in static- and shock-compression experiments, and are developing measurement systems and conducting XRD, XAFS, and other measurements systematically under static and shock compression. We are mainly focusing on phenomena which need an understanding of the time evolution and/or inhomogeneity, such as the collision of asteroids, mantle convection, and seismic activity (in geophysics) and the deformation and fracture of metals and ceramics (in materials science). The kick-off meeting was held in January 2016 and gathered a total of 34 researchers specialized in static- and shock-compression experiments and XAFS measurements.

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Tribology with Muon and Neutron

Project Leader: Hideki SETO

Tribology is the science of interacting surfaces in relative motion, which includes the study and application of the principles of friction, lubrication and wear. It is closely related to our everyday life, from live cell friction to engine lubrication and seismology. It is estimated that the reduction of energy consumption by the optimization of friction and lubrication is worth 1.3 trillion yen in Japan, and thus it is important to understand the fundamental aspects of tribology. However, elemental processes can be seen at various spatial scales from angstrom to km, and the phenomena are essentially non-equilibrium. Additionally, tribological phenomena occur at buried interfaces. Thus there are many unsolved problems, both theoretical and experimental.
In this project, we intend to utilize neutrons and muons to investigate friction and lubrication, because these probes are powerful tools for insitu investigation of buried interfaces, and also complementary methods to observe the dynamical behavior of molecules and molecular assemblies.

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Elements Strategy -Electron Materials-

Project Leader: Youichi MURAKAMI

Japan is reliant on imported supplies of actinide and rare-earth elements from foreign countries. Thus, there is a risk of a supply shortage of rare elements induced by the export control policy of resource-rich countries and the rapid increase in global demand of these elements. In order to avoid this situation, the functional substance is not composed of the rare elements but it is necessary to exhibit its function by a common element. For the purpose of achieving a strong comeback in materials science of fierce competition, national project "Element Strategy Project" was started from 2012. In the element strategy project, four areas directly competitive to Japanese industry were selected: electronic, magnetic, battery, and structural materials. We are aiming to develop entirely new material that does not use rare elements. Therefore in each material region the formation of the different fields collaborative research center with (1) material creation (2) theory of electronic state (3) analysis and evaluation are required.
For electronic materials region, Tokyo Institute of Technology (representative supervisor: Prof. Shigeo Hosono) was adopted, deputy base of the material evaluation and analysis the KEK (agency supervisor: Prof. Yoichi Murakami). In the Tokyo Institute of Technology for element strategy "TIES", we develop a material open based on successful experience far away from development policy, and pioneer a frontier element of electronic material to build new guidelines of material design, and then by making a material for practical use in the harm less elements it is intended to open up new material science. To achieve this goal, by the support of the theoretical calculations and advanced evaluation technology, we develop the effective system to create new materials, new high performance electronic materials containing no toxic element. In the KEK deputy base, we research the electronic structure, magnetic structure of the system, and the local structure of light elements such as hydrogen and oxygen in the material that material creation group was synthesized, those are precisely determined by using the synchrotron radiation and neutron scattering. The precise electronic structure of the interface and ultra-thin film also can be observed and evaluated by visualization of the depth distribution of electronic and chemical states. We will establish new technique that can further determine the magnetic phase diagram, the degree of spin freedom, identification of the charge state and hydrogen stable position measurement by using the muon.

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Elements Strategy -Magnetic Materials-

Project Leader: Kanta ONO

Elements Strategy Initiative Center for Magnetic Materials (ESICMM) at National Institute of Material Science (NIMS) put its goals on (1) laboratory-scale synthesis of mass-producible high-performance permanent magnets free of critical scarce elements for the next generation and (2) framework-building and provision of basic science and technology that are needed in industrial R&D activities. For these goals, ESICMM focuses on theoretical search and mining of new permanent magnet materials, and simultaneously pursue every possibility of processing technology to improve the existing high-performance permanent magnet materials through cooperative activities in three research fields of computer physics, structural and property characterization, and material processing. Another important mission of ESICMM is to edify scientists who will contribute to sustain future developments in magnetic functional materials.
In CMRC, "in situ analysis using neutrons and x-rays" project has been started in July 2012 as an analysis group member of ESICMM. Complementally use of neutrons at J-PARC/MLF and synchrotron x-rays at Photon Factory is very useful in the characterization of magnetic materials from atomic scale to micrometer scale.
Figures show some results in the project. Figure 1 indicates the magnetic structure of Nd2Fe14B permanent magnet obtained by neutron powder diffraction at iMATERIA beamline of J-PARC/MLF. We have successfully determined the magnetic structure using pulsed neutrons for a short beamtime about an hour. Figure 2 shows the spin-wave dispersion of Nd2Fe14B permanent magnet determined by neutron Brillouin scattering at HRC beamline of J-PARC/MLF. Figure 3 shows the single crystalline analysis results of Sm2Fe17N3 permanent magnet using x-ray diffraction system at Photon Factory.

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