Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Physical Society of Japan  

The Heusler compound Fe3−xMnxSi has been studied in various compositions and it exhibits complex magnetic properties at low temperatures. In ambient pressure at zero field, when x = 1.7, particularly, it orders ferromagnetically below TC ≈ 85 K, exhibits a transition to a phase with antiferromagnetic components at TA ≈ 67 K; furthermore, it orders antiferromagnetically at an even lower temperature of TA2 ≈ 60 K. For the dependence on the magnetic field of these transition temperatures, TA(B) and TA2(B), with increasing magnetic field, TA(B) changes only slightly, whereas TA2(B) shifts toward lower temperatures. In this study, magnetization measurements under pressures up to 1.2 GPa were performed to investigate pressure effects on transition temperatures and magnetic fields. The B–T magnetic phase diagram is presented, which summarizes the transition temperatures and magnetic fields obtained from these results. With increasing applied pressure, the TA2(B) line shows a shift toward the higher magnetic fields and temperatures, whereas TA(B) changes only slightly, and TC decreases and disappears around ∼1 GPa.

DOI： 10.7566/JPSCP.38.011135

researchmap

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AIP Publishing  

Superconducting properties were investigated in epitaxially layered films consisting of superconductor NbN and half-metallic Heusler alloy Co2MnSi (CMS). Temperature dependence of the electrical resistivity ρ(T) was measured by applying perpendicular magnetic fields to the surface of NbN/CMS films. With the increase of the CMS thickness dCMS, the upper critical field μ0Hc2 decreased monotonically, but the superconducting transition temperature Tc had the minimum of 10.1 K at dCMS ≈ 5 nm. The Tc behavior was in qualitative agreement with the theory of the π-coupling. The pair-breaking parameter δ determined by the superconducting fluctuation theory took the maximum at dCMS = 3 ∼5 nm, which would be related to the minimum of Tc. The experimental results reveal that the superconductivity of the NbN layer in NbN/CMS films is affected by the interplay between the superconducting NbN layer and the half-metallic CMS layer.

DOI： 10.1063/9.0000584

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The results of experimental investigations of the crystal structure, permeability, magnetization and Mössbauer spectroscopy of Co2ZrSn are reported. The sample, which was prepared by arc melting, comprised of a Heusler structure Co2ZrSn that coexisted with a small amount of an impurity phase. The Curie temperature TC of Co2ZrSn was found to be 452.3 K. At 1.8 K the magnetic moment of Co2ZrSn was estimated to be 2.0 μB/f.u., confirming that the magnetic moment of Co2ZrSn obeys the Slater-Pauling rule. The temperature variation of the spontaneous magnetization Ms roughly follows the Brillouin function for spin value S = 1/2. However, in the temperature region of T/TC > 0.6, Ms is distinctly higher than the Brillouin function. The TC of Co2ZrSn was almost independent of pressure. The Mössbauer spectroscopy measurements showed that the isomer shift I.S. (1.5 mm/s at 295 K) was approximately temperature independent. At 95 K the value of the hyperfine magnetic field HhfSn at the Sn nuclei was found to be 101 kOe. The temperature variation of HhfSn of Co2ZrSn roughly followed the Brillouin function for S = 1/2. On the basis of the experimental results, the electronic and magnetic properties of Co2ZrSn are discussed.

DOI： 10.1016/j.jpcs.2022.110635

Scopus

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

We report the magnetovolume effect of quaternary Heusler alloy CoFeCrAl as a potential candidate of spin gapless semiconductor. The crystal structure of CoFeCrAl was confirmed as the single phase of the ordered LiMgPdSn-type structure. From magnetization measurements at ambient pressure, the Curie temperature TC and the spontaneous magnetization Ms were determined to be 575.2 K and 2.01 μ B/f.u., respectively. The TC is higher enough than room temperature and the Ms follows the Slater-Pauling rule. High-pressure magnetization measurements showed that the Ms is almost independent of applying pressures not only at 10 K but also up to 300 K, exhibiting that the electronic state of CoFeCrAl is fully spin polarized and it is preserved even at 300 K. The experimental results reveal that the quaternary Heusler alloy CoFeCrAl is an attractive material for functional electrode ferromagnets in spintronics devices.

DOI： 10.1109/TMAG.2021.3096227

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

We report the critical behavior of the magnetization in Heusler alloy Co2TiGa0.8Sn0.2 as a potential candidate of high spin polarized materials with the characteristics of topological Weyl fermions. The Weyl semimetals are materials of great interest for applying spintronics devices, due to their unusual magnetoelectronic and magnetothermal properties. The magnetic properties of the synthesized Heusler alloy Co2TiGa0.8Sn0.2 are investigated around the Curie temperature TC. The magnetic isotherm measurements of Co2TiGa0.8Sn0.2 around TC exhibit that the critical exponent δ is deduced to be 4.455(4) in high maximum applied field of 50 kOe and 4.823(9) in low maximum applied field of 10 kOe, respectively. Both δ values are different from 3.0 derived by the conventional molecular field theory, but they are close to 5.0 predicted by the spin fluctuation theory for the itinerant electron ferromagnets. Possible origins for the discrepancy between experimental results and theoretical models are also discussed.

DOI： 10.1109/TMAG.2021.3097164

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physical Society of Japan  

Language：English   Publishing type：Research paper (scientific journal)  

Fe3−xMnxSi (x > 0.75) exhibits a ferromagnetic transition at TC and a transition to an antiferromagnetic phase with a ferromagnetic component at a temperature (TA) lower than TC, defined as the AF phase. Recently, in Fe1.3Mn1.7Si, another magnetic transition at a temperature lower than TA, defined as TA2, was observed. The phase below TA2 is referred to as the AF2 phase and is likely antiferromagnetic. This paper presents evidence for multiple phase transitions in Fe1.3Mn1.7Si obtained from specific heat and magnetization measurements. In addition, the magnetic transitions and magnetic properties of Fe3−xMnxSi (1.65 ≤ x ≤ 1.8) are investigated.

DOI： 10.7566/JPSJ.90.103701

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

We report experimental studies on Ru2-xFexCrSi focusing on properties related to antiferromagnetism in Ru2CrSi and spin glass (SG) in Ru1.9Fe0.1CrSi. By measuring the temperature dependence of magnetization M(T), specific heat C(T), electrical resistivity ρ(T), and muon spin relaxation (μSR), we observed that Ru2CrSi exhibited an antiferromagnetic (AF) transition at a temperature TN of ∼13 K, and Ru1.9Fe0.1CrSi showed SG properties that could be interpreted as successive SG transitions, where the spin-freezing occurred at temperature Tg, and below that strong irreversibility in M(T) and a gradual peak of M(T) at T∗(>Tg) appeared. When the data for 0≤x≤0.1 were compared, by substituting Fe the AF order was rapidly destroyed and it appeared to change to two anomalies at T∗ and Tg. With increasing x, there was a slight change in Tg from TN for x=0; however, T∗ increased, suggesting that the AF and the SG states are closely related. Furthermore, the results of specific heat, resistivity, and magnetization in high fields were presented and compared. For Ru2CrSi in specific heat under high magnetic fields up to 14 T, the peak shape around TN and the TN value were constant. The resistivity and magnetization in pulsed fields suggested that TN of Ru2CrSi was constant up to over 50 T. These results demonstrated the unusual robustness of the AF transition to magnetic fields. In Ru1.9Fe0.1CrSi, unusual hysteresis in magnetoresistance was observed in static and pulsed magnetic fields, although their appearances differed. These hystereses were considered a manifestation of the curious properties of the SG state with strong irreversibility.

DOI： 10.1103/PhysRevB.103.094428

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

It has been shown that Fe MnSi exhibits a ferromagnetic transition at Tc and an antiferromagnetic transition at a lower temperature, T , to a phase referred to as the AF phase. In a recent study on Fe Mn Si, another antiferromagnetic transition at a temperature lower than T , defined as T , was found, with the phase below T referred to as the AF2 phase. In this study, magnetic properties of Fe Mn Si are investigated for an x range of 1.65 ≤ x ≤ 1.85 in order to study theses transitions with varying x. For x ≥ 1.75, a transition characterized by a rather rapid decrease in the temperature dependence of magnetization is observed at a temperature lower than T at fields higher than ∼2 T. This implies the AF2-AF transition exists for x ≥ 1.75 as for x = 1.7. The magnetic field where the AF2-AF transition occurs increases with x, whereas at lower fields T does not depend strongly on x. Meanwhile, at near zero field, the ferromagnetic transition and spontaneous magnetization disappears for x ≥ 1.75, in contrast to the case for x = 1.7. This implies that the transition from paramagnetism directly to the AF2 phase occurs at low fields. These results are summarized in the B-T magnetic phase diagram. 2 A 1.3 1.7 A A2 A2 3-x x A A2

DOI： 10.1063/1.5080429

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Measurements of the electrical resistivity, magnetoresistance (MR), and Hall effects are performed to investigate the transport properties of Fe Mn Si (x = 1.6, 1.7, and 1.8) under magnetic fields. It is known that Fe MnSi exhibits a ferromagnetic transition at T and an antiferromagnetic transition at a lower temperature (T ) to the phase referred to as the AF phase. A recent study on Fe Mn Si found another antiferromagnetic transition at a temperature below T , defined as T , to a phase referred to as the AF2 phase. In this study, in MR measurements for x = 1.7 and 1.8, the change in MR with magnetic field is found to transition from positive to negative at certain magnetic fields. Comparing these results with those of magnetization measurements, these points correspond to the AF2-AF transitions. The results also indicate that these transitions occur at a higher field for x = 1.8 than for x = 1.7. The Hall effect measurements show the anomalous Hall effect for x = 1.6 and 1.7 in the temperature region where spontaneous magnetization is present, but not for x = 1.8, for which the ferromagnetic state appears to be absent. These results are consistent with the magnetization measurements. 3-x x 2 C A 1.3 1.7 A A2

DOI： 10.1063/1.5043075

Scopus

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

We investigated temperature dependence of differential conductance G(V) in planar junctions consisting of Co-based Heusler alloy Co2TiSn and superconductor Pb. Ferromagnetic Co2TiSn was predicted to be half-metal by first-principles band calculations. The spin polarization P of Co2TiSn was deduced to be 60.0% at 1.4K by the Andreev reflection spectroscopy. The G(V) spectral shape was smeared gradually with increasing temperature and its structure was disappeared above the superconducting transition temperature Tc. Theoretical model analysis revealed that the superconducting energy gap Δ was 1.06meV at 1.4K and the Tc was 6.8K, indicating that both values were suppressed from bulk values. However, the temperature dependent Δ(T) behavior was in good agreement with that of the Bardeen-Cooper-Schrieffer (BCS) theory. The experimental results exhibit that the superconductivity of Pb attached to half-metallic Co2TiSn was kept the conventional BCS mechanism characterized strong-coupling superconductors while its superconductivity was slightly suppressed by the superconducting proximity effect at the Co2TiSn/Pb interface.

DOI： 10.1016/j.physb.2017.10.055

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Transport properties were investigated for epitaxial films of superconductor NbN and half-metallic Heusler alloy Co2MnSi under high magnetic fields up to 17 T. The superconducting transition temperature Tc of NbN/Co2MnSi/Au trilayer films was determined to be 16.1K in the absence of magnetic field. Temperature dependence of the resistivity ρ(T) was measured in both magnetic fields parallel and perpendicular to the surface of NbN/Co2MnSi/Au trilayer films. The activation energy U0(H) for vortex motion of the trilayer films in both magnetic fields was well fitted above 5 T by the similar model with the exponents in the field dependence of the pinning force density. From the resistivity ρ(T) measurements under high magnetic fields, the upper critical field Hc2(0) at 0 K was also deduced to be μ0Hc2 ∥(0)=23.2T for the parallel magnetic filed and μ0Hc2 ⊥(0)=15.8T for the perpendicular magnetic field, respectively. The experimental results under magnetic fields revealed the superconductivity of the NbN layer was affected by the interplay between the superconducting NbN layer and the half-metallic Co2MnSi layer.

DOI： 10.1016/j.physb.2017.09.074

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Physics Publishing  

The magnetic properties of two Heusler compounds Fe1.3Mn1.7Si and Fe1.4Mn1.6Si are compared. Fe1.4Mn1.6Si exhibits a ferromagnetic transition at TC ∼ 117 K and another transition to a phase with antiferromagnetic components at TA ∼ 66 K, which is the same as the behavior of Fe2MnSi. Further, it is known that for Fe3-xMn x Si, with increasing x, TC decreases but TA remains almost constant, and they appear to meet around x ∼1.7. The careful measurements of magnetization at various magnetic fields reveal that Fe1.3Mn1.7Si has three transitions at low fields
for instance, at 0.01 T, the transition temperatures are found to be 85 K, 67 K, and 60 K. The lowest transition at 60 K is characterized by a rapid decrease in magnetization with decreasing temperature and significant magnetic field dependence, in contrast to the transition at TA , which is relatively independent of the magnetic field, for x = 1 and 1.6. The critical field at 0 K is ∼3 T. The transition at the lowest temperature was not found for x ≤ 1.6, and it is considered a different transition from that at TA . While the transition at the highest temperature 85 K is a ferromagnetic transition, the transition at 67 K has the characteristics of the transition at TA , and it is found to be insensitive to magnetic fields. They are revealed to be the same transitions as those at TC and TA for x ≤ 1.6.

DOI： 10.1088/1742-6596/969/1/012098

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Physics Publishing  

Fe2MnSi exhibits a ferromagnetic transition at TC and another transition to a phase with antiferromagnetic components at a low temperature of TA . By substituting V for Mn, so as to obtain Fe2Mn1-xV x Si, TA decreases with x and then vanishes around x ∼ 0.2. In this study, the magnetic transitions are investigated by magnetization measurements for Fe2Mn1-xV x Si (y = 1, 0 ≤ x ≤ 0.2) in high magnetic fields up to ∼70 T and for Fe1.5(Mn1-xV x )1.5Si (y = 1.5, 0 ≤ x ≤ 0.1) up to 5 T. For y = 1.5, with increasing x, TC increases and TA decreases as for y = 1, and the rate of the decrease in TA with x is slightly smaller than for y=1. In the low magnetic field region, TA for y = 1 does not significantly change due to the magnetic field but a distinct decrease is observed in high fields. The critical field at 0 K of this transition in Fe2MnSi is found to be larger than 70 T, and with increasing x, the critical field decreases corresponding to the decrease of TA at zero field.

DOI： 10.1088/1742-6596/969/1/012099

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physical Society  

Precise magnetization measurements of a half-metallic ferromagnet Co2TiSn with the Heusler type structure have been carried out under pressure up to 1.27 GPa. At ambient pressure, the spontaneous magnetic moment Msexp and the Curie temperature TCexp are experimentally obtained to be 1.993(3)μB/f.u. and 376.76(7) K, respectively. The Msexp is independent of applying pressure. The TCexp decreases with the increase of pressure and the pressure derivative of the Curie temperature dTCexp/dp is estimated to be -3.15(9) K/GPa. Furthermore, the pressure effect on the electronic and magnetic properties of Co2TiSn has been theoretically investigated on the basis of first-principles density functional calculations by using the projector augmented wave method in order to evaluate the half metallicity of Co2TiSn. Both the experimental and the theoretical results under pressure reveal that Co2TiSn is half metal. The experimental results of pressure-dependent magnetic properties are finally discussed on the basis of the spin fluctuation theory for itinerant electron magnetism.

DOI： 10.1103/PhysRevB.97.104414

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Institute of Physics Inc.  

We investigated the spin polarization P of Co-based Heusler alloy Co2FeSi by epitaxial contact Andreev reflection (ECAR) spectroscopy using epitaxially grown superconductor NbN and Heusler alloy Co2FeSi layered devices. Ferromagnetic Co2FeSi possesses the highest Curie temperature (TC ? 1100 K) and the largest spontaneous magnetic moment (ps ? 6 μB) in the class of Heusler alloys. The ECAR measurements revealed that the P value of Co2FeSi was 54 ± 2% with a finite barrier parameter Z, indicating that an intrinsic P value in ECAR spectroscopy would exceed reported values in point-contact Andreev reflection spectroscopy. We therefore established not only the epitaxial integration of ferromagnetic Co2FeSi with superconductor NbN on an MgO substrate but also the fabrication and evaluation techniques of their ECAR devices. This highly versatile superconducting spintronic system enables fundamental superconducting spintronic studies, and it is also a candidate for practical superconducting spintronic devices.

DOI： 10.1063/1.5007287

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We investigated the thermodynamic properties of Heusler compounds Fe2-xCox mnSi (0.00 <= x <= 2.00). The specific heats CP(T) for compounds with x <= 0.1 exhibit a.-type anomaly arising from spin rearrangements at TR. With increasing x, TR decreases linearly and vanishes at x similar to 0.169. The magnetic entropy, S-TR, derived from the magnetic specific heat, Cm(T), released at TR decreases by increasing x. This means the canting angle of spins from the [111] direction decreases by the substitution of Fe atoms with Co atoms, based on the magnetic structure model of Fe2MnSi proposed by Miles et al. For compounds with 0.5 <= x, CP(T) in the low-T range can be reproduced by Debye T-3 law. The electronic specific heat coefficient decreases monotonically with x.

DOI： 10.1016/j.jmmm.2016.12.070

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Two series of Heusler compounds Ru2Cr1-xXxSi (X = V, Ti) are synthesized, and their magnetic and electrical properties are investigated. Overall, these two series of compounds are identical in numerous properties. The measurements of magnetic properties reveal that an antiferromagnetic transition observed for x = 0 becomes smeared and it changes into a spin-glass state with increasing x. Around x = 0.5 this behavior disappears and it becomes paramagnetic. High-field magnetization for x = 03 and 0.4 up to 62 T exhibits no sign of magnetic transition or saturation of the magnetization. In the temperature dependence of resistivity, the kink that indicates the antiferromagnetic transition observed for x = 0 becomes invisible even for x similar to 0.1. This also exemplifies that the antiferromagnetic order is destroyed by the substitution and is replaced by the spin-glass state. Concerning the resistivity, these samples exhibit semiconducting behavior for small x, whereas with increasing x >= 0.5 they turn to show metallic behavior and Ru2VSi becomes a paramagnetic metal. Nevertheless, Ru2TiSi shows a tendency for semiconductivity again. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2016.09.276

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER PHYSICAL SOC  

Fe2MnSi exhibits a ferromagnetic transition at T-C similar to 230 K and another transition to a phase with antiferromagnetic components at T-A similar to 60 K. By substituting V for Mn, so as to obtain Fe2Mn1-xVxSi, T-A is revealed to decrease with x and then vanish around x similar to 0.2. In this study, the phase boundary of the transition at T-A in the high-field range is found for 0 <= x <= 0.15 with pulsed fields up to similar to 70 T. The magnetization of Fe2Mn1-xVx Si slowly increases even at the highest field of similar to 70 T, though it occurs more gradually as x increases. We compare the magnetization for 0 <= x <= 0.20 at 62 T with the Slater-Pauling rule, which holds when a Heusler compound is a half-metal, and find fairly good agreement. This suggests an intimate relation between the high-field phase and the half-metallic electronic structure, and that at the high-field limit the phase approaches the half-metallic state, which has been predicted by band-structure calculations.

DOI： 10.1103/PhysRevB.95.014410

Web of Science

Scopus

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

The substitution effect on half-metallicity for Co-based Heusler alloys Co2TiGa1-xSnx was investigated by experimental measurements and first-principles band calculations. The synthesized alloys crystalized in the ordered L2(1) crystal structure. The spontaneous magnetization obeyed the Slater-Pauling rule, indicating the possibility that Co2TiSn and Co2TiGa0.5Sn0.5 are half-metals. The first-principles band calculations revealed that Co2TiSn is half-metal and Co2TiGa0.5Sn0.5 is nearly half-metal. The spin polarization P was determined by the Andreev reflection technique. The intrinsic P values were 58.9% for Co2TiSn and 58.2% for Co2TiGa0.5Sn0.5, respectively. The P values of Co2TiGa1-xSnx were relatively higher than other Co-based Heusler alloys. Thus, Co-based Heusler alloys Co2TiGa1-xSnx are possible candidates for half-metallic electrode materials in spintronic devices.

DOI： 10.1109/LMAG.2016.2623257

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

We report structural, magnetic, and transport properties of epitaxial films of superconductor NbN and highly spin- polarized Heusler alloy CO2Fe0.4Mn0.6Si (CFMS). The saturation magnetization Ms of the film was 870 emu/cm(3), which is slightly smaller than values reported earlier. With an increase of CFMS thickness d(CFMS), the sheet resistance R-sq decreased and the upper critical field mu H-0(c2)(0) decreased monotonically, while the superconducting transition temperature Tc exhibited a minimum around d(CFMS) = 3 nm. A theoretical analysis of superconducting fluctuations revealed that the high spin polarization of the CFMS layer affected the pair breaking parameter d, the superconducting coherence length. (0), and the diffusion coefficient D.

DOI： 10.1109/LMAG.2017.2687878

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

We report tunnel experiments on Bi2Sr2Ca1-xYxCu 2O8+delta (Y-Bi2212) crystals with x= 0, 0.01, 0.05, 0.1, 0.11, and 0.12. The results are discussed about Cooper pairs existing. Tunneling spectra were measured for Y-Bi2212 crystal-SiO-Ag planar junctions. For superconducting samples the V-shaped gap structure and zero bias conductance peaks (ZBCP) were observed. While neither superconducting gap nor ZBCP was observed for insulator samples. These results suggest that Cooper pairs break up on the insulating side of superconductor- insulator transition (SIT). We also measured tunneling spectra on (Bi1-Pb-y(y))(2)Sr2Ca1-xYxCu2O8+delta samples. In their spectra there were also several characteristic behaviors.

DOI： 10.1109/TASC.2014.2351263

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.3.017018

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.3.014024

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.3.017017

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.7566/JPSCP.1.017013

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

We report spin polarization P of Fe-rich Heusler alloy Ru0.2Fe1.8CrSi, which was determined by the Andreev reflection technique. Heusler alloy Ru2-xFexCrSi was predicted to be half- metal by the first- principle band calculations. Fe- rich Ru0.2Fe1.8CrSi compounds are ferromagnetic and the saturation magnetization M-0 almost coincideswith that expected fromthe Slater- Pauling rule. Two theoretical approaches in the determination of spin polarization by Andreev reflection are discussed and compared from an experimental perspective. The spin polarization more than P = 0.60 is obtained for Ru0.2Fe1.8CrSi specimens and it is highest value in all Ru2-xFexCrSi compounds. The difference in values of spin polarization as determined by two models is less than 0.02.

DOI： 10.1109/TMAG.2013.2278034

Web of Science

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (bulletin of university, research institution)  

Language：English   Publishing type：Research paper (scientific journal)  

In the Heusler compound Ru2CrSi, an antiferromagnetic transition at T N =14 K was revealed by specific heat and magnetization measurements. In this study the electrical resistivity is measured in magnetic fields up to 14.5 T, and the antiferromagnetic transition in magnetic fields is investigated. In the temperature dependence of the resistivity at zero field, a clear dip at ∼15 K and a hump with a maximum at ∼ 9 K are observed. This dip is considered to be due to the antiferromagnetic transition. With increasing magnetic field, the magnitude of the resistivity slightly increases around T N
i.e., a positive magnetoresistance is observed. The temperature dependence of the resistivity is hardly affected by increasing the magnetic field. The transition temperature decreases only by ∼ 0.3 K even with applying 14.5 T. These results demonstrate that the antiferromagnetic state in Ru2CrSi is unusually unaffected by a strong magnetic field. © 2013 The Korean Physical Society.

DOI： 10.3938/jkps.62.2068

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：KOREAN PHYSICAL SOC  

We have measured the temperature (T) dependences of the electric resistivity, rho(T), and the specific heat, C (p) (T), of the ferromagnetic full-Heusler compound Ru2-x Fe (x) CrSi (1.3 a parts per thousand currency sign x a parts per thousand currency sign 1.8). rho(T) shows a metallic behavior (a,rho/a,T > 0) for 20 a parts per thousand(2) T a parts per thousand currency sign 300 K and nominal upturn at around 20 K for all samples. In the low-temperature range, C (p) (T) can be described by Debye's T (3) law. Although the coefficient of the lattice part of C (p) (T), beta, is insensitive for the Fe concentration x, the electronic specific heat part, gamma, decreases with increasing x. The values of the total densities of states (D (total) (E (F) )) estimated from gamma were 12.8, 10.1, and 9.6 states/f.u. eV for x = 1.3, 1.6, and 1.8, respectively. The values of majority spin band (D (a dagger)(E (F) )) and the minority spin band (D (a dagger")(E (F) )) were also estimated using gamma and the spin polarization P defined by Andreev-reflection experiments.

DOI： 10.3938/jkps.62.2063

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3379/msjmag.1305R007

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

The purpose of our present study is to understand the Superconductor-Insulator Transition. In this paper we report tunnel experiments on Bi2Sr2Ca1-xYxCu2O8+delta (Y-Bi2212) crystals with x = 0, 0.01, 0.05, 0.1, 0.11 and 0.12. The results are discussed about Copper pairs existing. Tunneling spectra were measured for Y -Bi2212 crystal-SiO-Ag planar junctions. For superconducting samples the V-shape gap structure and zero bias conductance peaks (ZBCP) were observed. While neither superconducting gap nor ZBCP was observed for insulating samples. These results suggest that Cooper pairs break up on the insulating side of SIT. In our spectra there were also several characteristic behaviors.

DOI： 10.1109/ASEMD.2013.6780707

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (other academic)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We report spin polarization P of Ru2-xFexCrSi Heusler alloys by the Andreev reflection technique. Ru2-xFexCrSi with L2(1)-type structure and saturation magnetic moment of 2 mu(B) per formula unit is theoretically predicted to be half-metals in the wide range of the composition x. We had clarified that the experimental results of saturation magnetic moment in Fe-rich compounds had coincided with the theoretical prediction. Therefore, we have measured the differential conductance of Ru2-xFexCrSi/Pb planar-type junctions. The P value of Ru2-xFexCrSi was determined by fitting the differential conductance with the modified Blonder-Tinkham-Klapwijk theory. We have found that the behavior of P for Ru2-xFexCrSi was independent of the composition x in the Fe-rich region: P=0.53 for both of x=1.5 and 1.7. The spin polarization is the similar value to Co-based Heusler alloys. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2010.10.062

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The properties of Heusler compounds Ru2-x Fe (x) CrGe are investigated and compared with those of Ru1.9Fe0.1CrSi. Ru2CrGe is confirmed to exhibit an antiferromagnetic transition with Ne,l temperature 13 K by magnetic susceptibility and specific heat measurements. When Fe is substituted for Ru, a peak in the magnetic susceptibility is observed, and in the lower temperature region irreversibility between temperature dependences of magnetization for zero-field-cooling and field-cooling conditions is found. Nevertheless, in specific heat of Ru1.9Fe0.1CrGe, there is no anomaly to indicate phase transition. The specific heat is almost identical to that for Ru1.9Fe0.1CrSi. The above results demonstrate that the magnetic states in the low temperature region of Fe-substituted samples are spin-glass-like states. Slight substitution of Fe for Ru destroys the long-range-order and lead to peculiar spin-glass-like states.

DOI： 10.1007/s10948-010-0967-6

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOP PUBLISHING LTD  

We investigated transport properties of the full-Heusler compound Ru2-xFexCrSi (x = 0.1), which is an insulator, under pressure P up to 8 GPa. The temperature dependence of electric resistance R(T) for Ru1.9Fe0.1CrSi is insensitive to pressure. R(T) is not described by the simple activation-type but -logT in the wide T and all P range we measured. This might be due to atomic disorder in the crystalline.

DOI： 10.1088/1742-6596/266/1/012011

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The effect of spin fluctuations on the transport properties in diffusive normal metal/d-wave superconductor (DN/DS) junctions is studied under various situations by solving the Usadel equation with Nazarov's generalized boundary condition. Tunneling conductance of the DN/DS junctions is calculated by changing the magnitude of the resistance in ON, Thouless energy in DN, the transparency of the insulating barrier, and the angle between the lobe direction of the d-wave pair potential and the normal to the interface, together with the magnitude of spin fluctuations. A zero-bias conductance dip (ZBCD) and a zero-bias conductance peak (ZBCP) occur in line shapes by way of a coherent Andreev reflection (CAR) around zero energy in the system of DN/DS junctions. We have found that both of the ZBCD and the ZBCP become narrower with the increasing magnitude of spin fluctuations. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2009.12.015

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We report spin polarization P of Ru2-xFexCrSi Heusler alloys by Andreev reflection technique. Ru2-xFexCrSi with the L2(1)-type structure is theoretically predicted to be half-metals in the wide range of the composition x. The experimental results of saturation moment in Fe-rich compounds measurements also support the theoretical prediction. We have measured the differential conductance of Ru2-xFexCrSi/Pb planar-type junctions. The P value of Ru2-xFexCrSi was determined by fitting the differential conductance with the modified Blonder-Tinkham-Klapwijk theory. The behavior of P was independent of the composition x in the Fe-rich region; P = 0.53 for x = 1.5 and P = 0.52 for x = 1.7, respectively. We have found that the spin polarization of Ru2-xFexCrSi in Fe-rich compounds was the similar values to Co-based Heusler alloys. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2010.01.044

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER PHYSICAL SOC  

We carried out magnetization M(T) and specific-heat C-P(T) measurements of the new Heusler compounds Ru2-xFexCrSi (x=0.1, 0.3, and 0.5), which exhibit spin-glass freezing. M(T) has peak- and irreversibility-type anomalies. The temperatures at which these anomalies appear have magnetic field dependence described by the Gabay-Toulouse and de Almeida-Thouless lines in the low-field range. For the magnetic specific heat C-m(T), we did not observe a discontinuity indicating long-range magnetic phase transition but a broad hump characteristic of spin-glass freezing. C-m(T) in the low-temperature range is described as a combination of linear- and quadratic-T terms. The quadratic-T dependence of C-m(T) is probably associated with excitation of the Ising component of the freezing spins.

DOI： 10.1103/PhysRevB.82.024406

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/PhysRevB.79.224423

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We report how spatial variations of the pair potential with an anisotropic symmetry influence tunneling conductance spectra in diffusive normal metal/insulator/d(x2-y2)-wave superconductor (DN/I/DS) junctions. A zero-bias conductance peak (ZBCP) was observed for the (110)-oriented interface in Ag/SiO/Bi2Sr2CaCu2O8+delta (Bi-2212) planar junctions. The experimental ZBCP was analyzed by the circuit theory, which was improved by the introduction of spatial variations of the pair potential near the junction interface between a DN conductor and a DS electrode. Our experimental results are well explained by the extended circuit theory for DN/I/DS junctions. (C) 2007 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2008.06.014

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The thermal broadening effect on the tunneling conductance in diffusive normal metal/triplet superconductor (DN/TS) junctions is studied based on the Usadel equation under the generalized boundary condition. The zero-bias conductance peak (ZBCP) enhances in the antinodal direction, due to the coexistence of the proximity effect and the midgap Andreev resonant states at the DN/TS junction interface. It is found that the ZBCP is affected by the thermal broadening effect especially for tunnel junctions with the low transparency and the small Thouless energy. (c) 2007 Elsevier B.V. All tights reserved.

DOI： 10.1016/j.physc.2007.04.007

Web of Science

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

We propose a new approach of smearing origins of a zero-bias conductance peak (ZBCP) in high-T-c superconductor tunnel junctions through the analysis based on the circuit theory for a d-wave pairing symmetry. The circuit theory has been recently developed from conventional superconductors to unconventional superconductors. The ZBCP frequently appears in line shapes for this theory, in which the total resistance was constructed by taking account of the effects between a d-wave superconductor and a diffusive normal metal (DN) at a junction interface, including the midgap Andreev resonant states (MARS), the coherent Andreev reflection (CAR) and the proximity effect. Therefore, we have analyzed experimental spectra with the ZBCP of Ag-SiO-Bi2Sr2CaCu2O8+delta (Bi-2212) planar tunnel junctions for the {110}-oriented direction by using a simplified formula of the circuit theory for d-wave superconductors. The fitting results reveal that the spectral features of the ZBCP are well explained by the circuit theory not only excluding the Dynes's broadening factor but also considering only the MARS and the DN resistance. Thus, the ZBCP behaviors are understood to be consistent with those of recent studies on the circuit theory extended to the systems containing d-wave superconductor tunnel junctions.

DOI： 10.1140/epjb/e2006-00440-2

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We propose a new interpretation about zero-bias conductance peak (ZBCP) behaviours in high-T-c superconductors. The ZBCP has been frequently observed in many tunneling spectroscopic experiments for unconventional superconductors. The ZBCP mechanism was well understood by the Andreev bound states theory for unconventional superconductors. On the other hand. the circuit theory has been recently developed from conventional superconductors to unconventional superconductors. The ZBCP often appears in this theory as well. Therefore, we have analyzed experimental spectra with the ZBCP of Bi2Sr2CaCu2O8+delta planar tunnel junctions by using both theories for d-wave paring symmetry. The experimental spectra are consistent with those of recent studies on the circuit theory for d-wave superconductors. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2005.10.096

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We report investigations of the smearing origin about a zero-bias conductance peak (ZBCP) observed in high-T-c superconductor (HTSC) tunnel junctions from the point of view of the circuit theory analysis for d-wave superconductors. The ZBCP enhancement was measured in Bi2Sr2CaCU2O8+delta-SiO-Ag planar tunnel junctions only for ab-plane directions. On the other hand, the circuit theory has been recently generalized from conventional superconductors to unconventional superconductors. The analysis in terms of the circuit theory reveals that the tunneling spectral behaviors of the ZBCP were well explained even when the Dynes's broadening factor was excluded from a tunneling spectral formula. Thus, the smearing effect in the ZBCP is understood by the influence of a diffusive normal metal resistance in the systems of HTSC tunnel junctions. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2005.05.019

Web of Science

Scopus

researchmap

Language：Japanese   Publishing type：Research paper (international conference proceedings)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We present magnetization properties of magnesium diboride (MgB2). MgB2 polycrystals were fabricated by using the vapor transport method inside a sealed stainless tube. The critical current density J(c) was estimated from the magnetization hysteresis DeltaM by using the Bean model. The temperature dependence of J(c) (T) showed a linear behavior below 15 K and deviated from such behavior in the higher temperature region. This behavior indicates that a flux creep effect influences the wide temperature range for the MgB2 polycrystals. Furthermore, small values of DeltaM show that the pinning force density F-p is very weak. The temperature dependence of the upper critical field H-c2 (T) was also obtained and revealed a linear behavior far from T-c. From our experimental results, we conclude that the MgB2 polycrystals are of good quality with less pinning centers, compared to the commercially available MgB2 powder. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0921-4534(03)01049-9

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Effects of Y substitution on the magnetic hystereses are investigated in Y-substituted YxGd1-xBa2Cu3O7-delta ceramics. Magnetizations are first measured at respective constant temperatures, where the hysteresis DeltaM is estimated by the magnetization difference between field increase and decrease. When the variations of DeltaM for the identical field against temperatures are examined, DeltaM is found to obey DeltaM = A exp[-T/T-0] with the single To for a given field. The characteristic temperature T-0 is in the range of 10-30 K, and the field dependence is compared with the function: H-1/n. The field dependence of T-0 for the x = 0.2 (nominal) sample is larger than that for the pure Gd123 ceramics of x = 0, reflecting larger T-0 at lower magnetic fields. This is owing to larger DeltaM at higher temperatures and lower fields in the Y-substituted system. Improvement of the intergrain coupling by the Y substitution is discussed in comparison with magnetic behaviors in the pure sample. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0921-4534(03)00848-7

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Field and temperature dependence of magnetization and also time dependent magnetization (flux creep) of powdered MgB2 specimens have been measured by using a SQUID magnetometer in the temperature range of 4.5 less than or equal to T less than or equal to 37 K and under the field up to 1 T. Scaling plots of normalized pinning force density F-p/F-p max as a function of normalized flux density B/B-max in the temperature range of 25 less than or equal to T less than or equal to 37 K showed that a two dimensional pinning is dominant for the flux pinning of the specimens. Another distinct feature is that a linear reduction of J(c) with increasing temperature at temperatures lower than 30 K and a quadratic decrease at higher temperatures than 35 K have been observed. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(02)02707-7

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We report that a large superconducting gap has been observed in some tunneling spectra of Bi2Sr2CaCu2O8+delta (Bi2212). The observed gap magnitude is roughly twice as large as those of the recent studies of Bi2212. Magnetic susceptibility measurements reveal that the single crystals retain a single phase of Bi2212. Therefore, the experimental results suggest that the large gap arises by way of the superconductor-insulator-superconductor (SIS) tunnel junction, due to the junction interface of the crystal boundary. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(03)00627-0

Web of Science

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Magnetic hysteresis measurements are performed in GdBa2Cu3O7-delta ceramics, and effects of magnetic field, temperature and substitution are studied. The hysteresis DeltaM is found to decay exponentially with temperature: DeltaM proportional to exp[-T/T-0]. The activation temperature T-0 varies mildly around 20 K, which seems to depend on the magnetic field as H-1/n. Substitution tends to increase DeltaM at lower fields. The results are examined in relation to ceramic nature of the sample. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(02)02549-2

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We present the temperature dependence of tunneling spectra of as-grown Bi2Sr2CaCu2O8+delta single crystals. An enhancement of the zero-bias conductance peak (ZBCP) was observed for the ab-plane tunnel junctions. The ZBCP has appeared below the bulk superconducting critical temperature T-c. This experimental result suggests that the ZBCP obviously arises by way of the superconducting gap and not the pseudogap. This result is consistent with recent studies of the Andreev bound states model for d-wave superconductors. (C) 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(02)01434-X

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

We report the experimental results of quasiparticle tunneling using Bi2Sr2CaCu2O8+δ-SiO-Ag planar junctions. We have measured the (0 0 1)-, (1 0 0)- and (1 1 0)-oriented junctions. For the in-plane ab oriented junctions, a reproducible zero bias conductance peak has been observed. We have analyzed the data by using the extended Andreev bound states model for d-wave superconductors and have considered the roughness effect by averaging over in-plane directions. The experimental results are consistent with the theoretical calculations. © 2001 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(01)00207-6

Scopus

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PHYSICAL SOC JAPAN  

We report the experimental results of quasiparticle tunneling using Bi2Sr2CaCu2O8+delta (BSCCO)-SiO-Ag planar junctions. For the {001}-oriented junctions, we have measured a well-known V-shaped gap structure expected for d-wave superconductors. For the {100}- and {110}-oriented junctions, a reproducible zero bias conductance peak (ZBCP) enhancement has been observed. The temperature dependence of the ZBCP is also presented. The ZBCP was observed below T-c. Our results are consistent with those of recent studies on the Andreev reflection between a d-wave superconductor and a normal metal.

DOI： 10.1143/JPSJ.69.2743

Web of Science

Scopus

researchmap

Authorship：Lead author   Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

researchmap

Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (bulletin of university, research institution)  

researchmap

Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(東京大学駒場キャンパス)   Country：Japan  

Event date： 2021.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(東京大学駒場キャンパス)   Country：Japan  

Event date： 2021.2

Language：English   Presentation type：Poster presentation  

Venue：Online (Tohoku University, Sendai, Japan)   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(宮崎大学木花キャンパス)   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(宮崎大学木花キャンパス)   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(宮崎大学木花キャンパス)   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(宮崎大学木花キャンパス)   Country：Japan  

Event date： 2020.12

Language：English   Presentation type：Poster presentation  

Venue：On Internet Space (Institute for Materials Research, Tohoku University, Sendai, Japan)   Country：Japan  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(鹿児島大学郡元キャンパス)   Country：Japan  

Event date： 2020.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(鹿児島大学郡元キャンパス)   Country：Japan  

Event date： 2020.9

Language：Japanese   Presentation type：Poster presentation  

Venue：オンライン開催(熊本大学黒髪キャンパス)   Country：Japan  

Event date： 2020.9

Language：Japanese   Presentation type：Poster presentation  

Venue：オンライン開催(熊本大学黒髪キャンパス)   Country：Japan  

Event date： 2020.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン開催(熊本大学黒髪キャンパス)   Country：Japan  

Event date： 2020.9

Language：Japanese   Presentation type：Poster presentation  

Venue：オンライン開催(熊本大学黒髪キャンパス)   Country：Japan  

Event date： 2020.3

Language：Japanese   Presentation type：Poster presentation  

Venue：名古屋大学東山キャンパス   Country：Japan  

Event date： 2020.3

Language：Japanese   Presentation type：Poster presentation  

Venue：名古屋大学東山キャンパス   Country：Japan  

Event date： 2019.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学大学院総合理工学府筑紫キャンパス   Country：Japan  

Event date： 2019.12

Language：Japanese   Presentation type：Poster presentation  

Venue：九州大学大学院総合理工学府筑紫キャンパス   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：佐賀大学本庄キャンパス   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：佐賀大学本庄キャンパス   Country：Japan  

Event date： 2019.11

Language：English   Presentation type：Poster presentation  

Venue：Duy Tan University, Danang, Vietnam   Country：Viet Nam  

Event date： 2019.11

Language：English   Presentation type：Poster presentation  

Venue：Duy Tan University, Danang, Vietnam   Country：Viet Nam  

Event date： 2019.9

Language：Japanese   Presentation type：Poster presentation  

Venue：岐阜大学柳戸キャンパス   Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岐阜大学柳戸キャンパス   Country：Japan  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岐阜大学柳戸キャンパス   Country：Japan  

Event date： 2019.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2019.3

Language：Japanese   Presentation type：Poster presentation  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2018.10

Language：Japanese   Presentation type：Poster presentation  

Venue：TPKガーデンシティ熊本(熊本市)   Country：Japan  

Event date： 2018.9

Language：Japanese   Presentation type：Poster presentation  

Venue：同志社大学京田辺キャンパス   Country：Japan  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：同志社大学京田辺キャンパス   Country：Japan  

Event date： 2018.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：同志社大学京田辺キャンパス   Country：Japan  

Event date： 2018.9

Language：Japanese   Presentation type：Poster presentation  

Venue：同志社大学京田辺キャンパス   Country：Japan  

Event date： 2018.7

Language：English   Presentation type：Poster presentation  

Venue：The Moscone Center, San Francisco, California, USA   Country：United States  

Event date： 2018.7

Language：English   Presentation type：Poster presentation  

Venue：The Moscone Center, San Francisco, California, USA   Country：United States  

Event date： 2018.7

Language：English   Presentation type：Poster presentation  

Venue：The Moscone Center, San Francisco, California, USA   Country：United States  

Event date： 2018.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京理科大学野田キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：ホテル中山荘(都城市)   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Poster presentation  

Venue：ホテル中山荘(都城市)   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Poster presentation  

Venue：ホテル中山荘(都城市)   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島大学郡元キャンパス   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岩手大学上田キャンパス   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Poster presentation  

Venue：岩手大学上田キャンパス   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岩手大学上田キャンパス   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岩手大学上田キャンパス   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岩手大学上田キャンパス   Country：Japan  

Event date： 2017.8

Language：English   Presentation type：Poster presentation  

Venue：The Swedish Exhibition Centre/Gothia Towers, Gothenburg, Sweden   Country：Sweden  

Event date： 2017.8

Language：English   Presentation type：Poster presentation  

Venue：The Swedish Exhibition Centre/Gothia Towers, Gothenburg, Sweden   Country：Sweden  

Event date： 2017.7

Language：English   Presentation type：Poster presentation  

Venue：The Clarion Congress Hotel, Prague, the Czech Republic   Country：Czech Republic  

Event date： 2017.7

Language：English   Presentation type：Poster presentation  

Venue：The Clarion Congress Hotel, Prague, the Czech Republic   Country：Czech Republic  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡大学   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡大学   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡大学   Country：Japan  

Event date： 2016.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡大学   Country：Japan  

Event date： 2016.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：くまもと県民交流館パレア   Country：Japan  

Event date： 2016.11

Language：Japanese   Presentation type：Poster presentation  

Venue：くまもと県民交流館パレア   Country：Japan  

Event date： 2016.8

Language：English   Presentation type：Poster presentation  

Country：Taiwan, Province of China  

Event date： 2016.8

Language：English   Presentation type：Poster presentation  

Country：Taiwan, Province of China