出版者・発行元：Communications Materials  

Van der Waals (vdW) two-dimensional (2D) materials have unleashed unprecedented opportunities to probe emerging physics that could be potential candidates for various functional applications. In particular, vdW 2D magnetic materials exhibit significant potential for advanced spintronic devices. Recently, Fe3GaTe2 has been discovered to possess the room-temperature ferromagnetic property with an intrinsic perpendicular magnetic anisotropy (PMA). Furthermore, considerably large anomalous Hall and Nernst angles have been reported recently. These groundbreaking findings pave the way for significant advances in high density random-access memory as well as energy harvesting devices based on spin conversion. Enhancements in the PMA and Curie temperature contribute to improved performance with reliable operation in a wide temperature range above room temperature. Moreover, the exploration of giant anomalous Hall and Nernst angles is a crucial factor for the efficient operation of spintronic devices. In this study, we demonstrate that the application of pressure to the Fe3GaTe2 2D ferromagnetic film strengthens the interlayer coupling, resulting in an improved PMA property. In addition, the application of pressure has been found to significantly increase the anomalous Hall angle. Our findings suggest that the application of pressure effectively controls the vdW interlayer coupling, thereby manipulating the ferromagnetic and spin-conversion properties of the 2D materials.

DOI： 10.1038/s43246-024-00665-3

Web of Science

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出版者・発行元：Journal of the Physical Society of Japan  

We investigated the superconducting properties of a palladium hydride (PdHx; x = H=Pd) film with a thickness of ∼100 nm prepared by a low-temperature hydrogen (H) absorption method. H atoms were loaded to a Pd film in H2 gas pressure of ∼0.25 MPa at temperatures of T = 180 and 150 K. At T = 180 K, after the resistivity variation due to H absorption was almost stopped, the PdHx film was cooled rapidly to low temperatures for the resistivity measurements. A superconducting transition was observed at Tc ∼ 1.1 K, where the transition width is smaller than 0.1 K. This indicates that a high-quality sample with a sharp transition can be obtained by providing sufficient time for H absorption. At T = 150 K, although the resistivity variation remained, the film was cooled. The transition temperature Tc increased to ∼2.1 K, whereas the transition width increased owing to the inhomogeneity of the H concentration in the film. Curiously, regardless of the H homogeneity, there remained a similar T-dependent residual resistivity in both films prepared at T = 180 and 150 K after the superconducting transition. This implies that the observed residual resistivity is essential for the future of the system, although its origin is not clear.

DOI： 10.7566/JPSJ.93.024703

Web of Science

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出版者・発行元：IEEE Transactions on Magnetics  

We have experimentally and theoretically investigated the influence of pressure on the spin Hall effect (SHE) for the Pt. The experimental results using a laterally configured Pt/CoFeB hybrid nanostructure suggest that the spin Hall angle for the Pt is almost constant under pressure up to 2 GPa. The theoretical study based on the first-principles calculation found the spin Hall conductivity for the Pt shows a 10% reduction due to the pressure application of 75 GPa, supporting the experimental results. These results imply that the enhanced spin Hall signal in the dynamical spin injection due to the pressure application is caused by the enhancement of the interfacial spin mixing conductance.

DOI： 10.1109/TMAG.2023.3283467

Web of Science

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出版者・発行元：Applied Physics Express  

We experimentally investigate the influence of the pressure on the spin-charge conversion efficiency in a CoFeB/Pt bilayer system by using a specially designed pressure-cell setup. The dc voltage spectra under the dynamical spin injection is found to show the systematic increase with increasing pressure. These modifications can be understood by the enhancement of the spin-charge conversion efficiency due to the modulation of the spin-orbit interaction and/or the exchange interaction at the interface. The present demonstration indicates that the pressure provides a tunable functionality for the physical constants in spintronic devices.

DOI： 10.35848/1882-0786/ac5501

Web of Science

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