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山崎 匠*; 平井 孝昌*; 八木 貴志*; 山下 雄一郎*; 内田 健一*; 関 剛斎*; 高梨 弘毅
Physical Review Applied (Internet), 21(2), p.024039_1 - 024039_11, 2024/02
被引用回数：0 パーセンタイル：0.01(Physics, Applied)This study presents a measurement method for determining the figure of merit for transverse thermoelectric conversion in thin-film forms. Leveraging the proposed methodology, we comprehensively investigate the transverse thermoelectric coefficient, in-plane electrical conductivity, and out-of-plane thermal conductivity in epitaxial and polycrystalline Fe/Pt metallic multilayers.
Chen, J.*; 山本 慧; Zhang, J.*; Ma, J.*; Wang, H.*; Sun, Y.*; Chen, M.*; Ma, J.*; Liu, S.*; Gao, P.*; et al.
Physical Review Applied (Internet), 19(2), p.024046_1 - 024046_9, 2023/02
被引用回数：6 パーセンタイル：87.72(Physics, Applied)Coherent coupling in magnon based hybrid system has many potential applications in quantum information processing. Magnons can propagate in magnetically ordered materials without any motion of electrons, offering a unique method to build low-power-consumption devices and information channels free of heat dissipation. In this article, we demonstrate the coherent propagation of hybridized modes between spin waves and Love surface acoustic waves in a multiferroic BiFeO
and ferromagnetic La
Sr
MnO based heterostructure. The magneto-elastic coupling enables a giant enhancement of strength of the hybridized mode by a factor of 26 compared to that of the pure spin waves. A short wavelength down to 250 nm is demonstrated for the hybridized mode, which is desirable for nanoscale acousto-magnonic applications. Our combined experimental and theoretical analyses represent an important step towards the coherent control in hybrid magnonics, which may inspire the study of magnon-phonon hybrid systems for coherent information processing and manipulation.
増田 啓人*; 関 剛斎*; 山根 結太*; Modak, R.*; 内田 健一*; 家田 淳一; Lau, Y.-C.*; 深見 俊輔*; 高梨 弘毅
Physical Review Applied (Internet), 17(5), p.054036_1 - 054036_9, 2022/05
被引用回数：6 パーセンタイル：70.93(Physics, Applied)反対称層間交換結合(AIEC)が最近発見され、人工反強磁性体(SAF)の傾角磁化の誘起を通じた磁化スイッチングにおいて極めて重要な役割を果たしている。本研究では、くさび形の層を持つ垂直磁化多層膜Pt/Co/Ir/Co/Ptにおける大きなAIECを報告をする。AIECの有効磁場は、対称的な層間交換結合に関連しており、AIECを強化するための指針を提供する。SAFに対する拡張Stoner-Wohlfarthモデルを開発し、その磁化スイッチングの重要な要素を明らかにする。理論的知識と実験結果を組み合わせることで、面内磁場のみによる垂直磁化スイッチングが達成される。
Schreiber, F.*; Meer, H.*; Schmitt, C.*; Ramos, R.*; 齊藤 英治; Baldrati, L.*; Kl
ui, M.*
Physical Review Applied (Internet), 16(6), p.064023_1 - 064023_9, 2021/12
被引用回数：3 パーセンタイル：26.56(Physics, Applied)We analyze the complex impact of the local magnetic spin texture on the transverse Hall-type voltage in device structures utilized to measure magnetoresistance effects. We find a highly localized and asymmetric magnetic sensitivity in the eight-terminal geometries that are frequently used in current-induced switching experiments, for instance, to probe antiferromagnetic materials. Using current-induced switching of antiferromagnetic NiO/Pt as an example, we estimate the change in the spin Hall magnetoresistance signal associated with switching events based on the domain-switching patterns observed via direct imaging. This estimate correlates with the actual electrical data after subtraction of a nonmagnetic contribution. Here, the consistency of the correlation across three measurement geometries with fundamentally different switching patterns strongly indicates a magnetic origin of the measured and analyzed electrical signals.
小林 正起*; Anh, L. D.*; 鈴木 雅弘*; 金田-高田 真悟*; 竹田 幸治; 藤森 伸一; 芝田 悟朗*; 田中 新*; 田中 雅明*; 大矢 忍*; et al.
Physical Review Applied (Internet), 15(6), p.064019_1 - 064019_10, 2021/06
被引用回数：5 パーセンタイル：35.58(Physics, Applied)A fundamental understanding of the interfacial magnetic properties in ferromagnetic heterostructures is essential for utilizing ferromagnetic materials for spintronic device applications. Here, we investigate the interfacial magnetic and electronic structures of epitaxial single-crystalline LaAlO
(LAO)/La
Sr
MnO(LSMO)/Nb:SrTiO(Nb:STO) heterostructures with varying LSMO layer thicknesses, in which the magnetic anisotropy strongly changes with the LSMO thickness due to the delicate balance between strains originating from both the Nb:STO and LAO layers, using X-ray magnetic circular dichroism and photoemission spectroscopy. We successfully detect the clear change of the magnetic behavior of the Mn ions concomitant with the thickness-dependent metal-insulator transition. Our results suggest that the double-exchange interaction induces ferromagnetism in the metallic LSMO film under tensile strain caused by the STO substrate, while the superexchange interaction determines the magnetic behavior in the insulating LSMO film under compressive strain originating from the top LAO layer. The change in strain, depending on LSMO layer thickness, is confirmed by scanning transmission electron microscopy. Based on those findings, the formation of a magnetic dead layer near the LAO/LSMO interface is attributed to competition between the superexchange interaction via Mn 
orbitals under compressive strain and the double-exchange interaction via the 
orbitals. These findings provide key aspects of ferromagnetic oxide heterostructures for the development of spintronic device applications.
日置 友智*; 橋本 佑介*; Johansen, T. H.*; 齊藤 英治
Physical Review Applied (Internet), 11(6), p.061007_1 - 061007_5, 2019/06
被引用回数：7 パーセンタイル：36.99(Physics, Applied)We investigate the propagation dynamics of magneto-elastic waves in an out-of-plane (OP) magnetized film using time-resolved magneto-optical (TRMO) microscopy based on the Cotton-Mouton effect. In OP magnetized films, spin precession induces a temporal change in the in-plane component of magnetization (
), which can be measured through birefringence induced by , or the Cotton-Mouton effect (CME). Here we develop an imaging method based on CME, realizing the observation of stress-driven magneto-elastic waves in an OP magnetized film. This result expands the focus of TRMO microscopy, allowing investigation of magneto-elastic waves in OP magnetized films.
PS
metastable crystal森 一広*; 延壽寺 啓悟*; 村田 駿*; 柴田 薫; 川北 至信; 米村 雅雄*; 小野寺 陽平*; 福永 俊晴*
Physical Review Applied (Internet), 4(5), p.054008_1 - 054008_6, 2015/11
被引用回数：41 パーセンタイル：82.41(Physics, Applied)J-PARCセンター物質生命科学実験施設MLFに設置されている中性子準弾性散乱装置DNAを利用して、全固体リチウムイオン電池の固体電解質として有望なLiPS準安定結晶のリチウムイオン伝導経路を解明し、リチウムイオンの動きを直接観測することに成功した。
