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Xue, J.*; Huang, D.*; 服部 高典; Li, L.*; Feng, Y.*; Wang, H.*; Fan, X.*; Yao, J.*; Wang, Y.*; Liu, Z.*; et al.
Applied Physics Letters, 128(20), p.201903_1 - 201903_8, 2026/05
被引用回数：0 パーセンタイル：0.00(Physics, Applied)NH
Iのサイクル疲労およびバロカロリック応答は、最大100MPaの応力を伴う加圧・減圧サイクル下で直接評価され、100サイクルの後に断熱温度変化(
)は15Kから約0.8Kまで減少した。emphその場X線回折、ラマン分光法、および中性子回折を併用した解析により、最初の荷重除去後であっても残留高圧相が存在することが明らかになり、その割合は100サイクル目までに急速に90%まで増加した。この疲労挙動を解明するために現象論的モデルが構築され、実験データとの良好な一致が得られた。粒界応力を緩和し、結晶粒の移動性を高めるため、NHI粒子とシリコーンオイルからなる複合体を、3Dプリントされたポリマーシェルに封入した。このような構造設計により、バロカロリック効果のサイクル安定性が著しく向上し、100サイクル後でもは約4.6Kまで上昇した。我々の結果は、気圧熱効果の疲労挙動に関する基礎的な理解を確立するとともに、実用的な気圧熱冷却技術への実現可能な道筋を示すものである。
荒木 康史; 家田 淳一
Applied Physics Letters, 128(9), p.092406_1 - 092406_7, 2026/03
被引用回数：0 パーセンタイル：0.00(Physics, Applied)The spin Hall effect in a heavy metal intercorrelates an AC electric current to the magnetization dynamics in an adjacent ferromagnet, which manifests as an electric reactance in the system's current-voltage response. We present a comprehensive theoretical analysis for this emergent reactance contribution in the frequency regime relevant to transport measurements up to a few GHz. Our analysis reveals that the reactance becomes inductor-like at low frequency below the ferromagnetic resonance. Crucially, we find that the sign of the reactance is directly governed by the spin transfer mechanism at the interface, which depends on the competition between its damping-like and field-like components parametrized by the spin mixing conductance. This characteristic behavior in the reactance offers a powerful transport observable in distinguishing the interfacial spin transfer processes in spintronic materials.
埋田 真樹; 中堂 博之; 今井 正樹; 松尾 衛; 佐藤 奈々; 森 道康; 前川 禎通*; 齊藤 英治
Applied Physics Letters, 128(12), p.122402_1 - 122402_6, 2026/03
被引用回数：0 パーセンタイル：0.00(Physics, Applied)The unidirectional spontaneous rotation of particles caused by Brownian motion rectified by the Coriolis force is reported. Fine magnetic particles dispersed in a revolving liquid were observed using the Barnett effect, and we found that the particles rotated much faster than the liquid. The observed spontaneous extra rotation is attributed to the breaking of the time-reversal symmetry of the Coriolis force, which rectified the random Brownian motion affected by viscosity. Our model considering molecular fluctuations in the medium reproduced the experiments well. The present results also suggest that all objects floating in fluids on Earth rotate spontaneously because of fluctuations.
遠藤 達朗*; 荒木 康史; 関 宗俊*; 田畑 仁*; 田中 雅明*; 大矢 忍*
Applied Physics Letters, 128(2), p.022405_1 - 022405_6, 2026/01
被引用回数：0 パーセンタイル：0.00(Physics, Applied)Perovskite transition metal oxides (TMOs) are hallmark systems for studying electron correlations, with strong Coulomb interactions reaching the electron volt scale. Such interactions generally hinder coherent charge transport, limiting its observation to only moderately correlated TMOs. Among TMOs with strong electron correlations, the ferromagnetic perovskite manganite La
Sr
MnO
(LSMO) has attracted significant attention for spintronics applications due to its half-metallic nature and robust ferromagnetism, with a Curie temperature above room temperature. In this Letter, we report the emergence of oscillatory conduction in tunnel diodes incorporating an epitaxial thin LSMO layer - a phenomenon not previously observed in strongly correlated oxides. The observed oscillations originate from discrete quantum-well states formed via quantum confinement, indicating coherent transport across the LSMO layer. These quantum-well states are quantitatively explained using a tight-binding model tailored for the electronic structure of LSMO. Our findings demonstrate that high- quality epitaxial perovskite manganites can sustain coherent transport, even in the presence of strong electron correlations, offering avenues for oxide-based quantum and spintronics devices.
深谷 有喜; 松田 巌*
Applied Physics Letters, 127(26), p.263102_1 - 263102_6, 2025/12
被引用回数：0 パーセンタイル：0.00(Physics, Applied)本研究では、全反射高速陽電子回折(TRHEPD)法を用いて、Ag(111)表面上に成長させたビスマセン(グラフェンのビスマス版)の原子配置を詳細に解析した。ビスマセン由来の回折スポットに着目した結果、[
]および[
]方位に対してペアとなるロッキング曲線のプロファイルに有意な差が認められなかった。これは、ビスマセンが平坦なハニカム格子で構成されていることを示唆する。動力学的回折理論に基づく強度計算を行ったところ、単位胞内の2つのビスマス原子はAg(111)層に対して同一高さに位置していることが明らかになった。さらに、ビスマセンとAg(111)の第一層におけるデバイ温度は、バルク材料と比較して低下していることが判明した。これらの結果は、ビスマセンの特異なトポロジカル特性を理解するための基礎的な構造情報を提供する。
-ordered FePt thin films studied by angle-dependent X-ray magnetic circular dichroism芝田 悟朗; 池田 啓祐*; 高梨 弘毅; 藤森 淳*; 他8名*
Applied Physics Letters, 127(14), p.142406_1 - 142406_6, 2025/10
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We have investigated the contribution of the Fe 
electrons to its magnetic anisotropy energy by angle-dependent X-ray magnetic circular dichroism at the Fe 
edge. By this technique, one can deduce the magnetic dipole moment 
, which represents the anisotropic spatial distribution of spin-polarized electrons, and the orbital moment anisotropy (OMA) of Fe electrons. Detected finite indicates that the spin-polarized Fe electrons are distributed preferentially in the out-of-plane direction of the films. This of Fe overwhelms the positive contribution of OMA to PMA, and reduces the PMA of -ordered FePt thin films, consistent with a previous first-principles calculation. The present result implies that a large positive contribution of the non-magnetic element Pt rather than Fe governs the PMA of -ordered FePt thin films.
社本 真一; Shin, K.*; 赤津 光洋*; 今井 正樹; 植田 大地*; 横尾 哲也*; 根本 祐一*; Hassan, A. M. A.*; Chang, L.-J.*; 家田 淳一; et al.
Applied Physics Letters, 127(13), p.132403_1 - 132403_5, 2025/09
被引用回数：0 パーセンタイル：0.00(Physics, Applied)FeTiO is an ilumenite antiferromagnetic insulator with Fe
. Two-dimensional ferromagnetic honeycomb layers are antifferomagnetically stacked along the 
-axis. The magnetic Bragg peak intensity is enhanced by ultrasound injection up to 300 % on the FeTiO crystal at low temperatures. The large enhancement is attributed to the large spin-lattice coupling of Fe in FeTiO. The enhancement is lost above 35 K, suggesting that the energy splitting of the Fe levels by the spin-orbit coupling is about 35 K. This finding opens a possibility for high efficiency acoustic spin pumping.
Fe
|Pt at room temperature平田 裕也*; 吉川 貴史; 有沢 洋希*; 齊藤 英治*
Applied Physics Letters, 126(25), p.252408_1 - 252408_5, 2025/06
被引用回数：6 パーセンタイル：81.32(Physics, Applied)The nonlinear Seebeck effect, nonlinear conversion of a temperature gradient into an electric current, was observed at room temperature. Based on a second-harmonic lock-in method combined with an a.c. temperature gradient, 
, we measured a nonlinear Seebeck voltage in NiFe|Pt bilayers at 300 K, the amplitude of which increases in proportion to 
. We also observed that the nonlinear Seebeck voltage increases as the sample length along the direction decreases, showing a characteristic scaling law distinct from the conventional linear Seebeck effect. We developed a phenomenological model for the nonlinear Seebeck effect incorporating the spin-current induced modulation of the Seebeck coefficient, which well reproduces the experimental results.
芝田 悟朗; 他9名*
Applied Physics Letters, 126(24), p.241902_1 - 241902_6, 2025/06
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We performed hard X-ray photoemission spectroscopy (HAXPES) experiments of bulk single-crystalline InGaZnO (sc-IGZO), which was recently synthesized via the optical floating zone method, in order to reveal the bulk intrinsic electronic structure. We find that oxygen vacancies are preferentially located around In atoms in as-grown crystals, which are filled out by post-annealing in an oxygen atmosphere. The subgap states near the valence-band maximum (VBM) were much weaker than those in the previous study even without oxygen annealing, which suggests that the loss of crystallinity is relevant to the formation of them in addition to the oxygen vacancies.
Huang, Y.-C.*; 吉川 貴史; 他5名*
Applied Physics Letters, 126(9), p.092403_1 - 092403_6, 2025/03
被引用回数：0 パーセンタイル：0.00(Physics, Applied)The application of spin-current volume effect (SVE) with volume magnetostriction of iron gallium (FeGa) films is examined for micro-diaphragm actuation. A silicon diaphragm measuring 1.5
1.5 mm
is coated with Pt (100-nm-thick) and FeGa (100-nm-thick) thin films. An alternating charge current passed through the FeGa/Pt/Si diaphragm under a magnetic field perpendicular to the charge current generates an alternating spin current via the spin Hall effect in the Pt film, transferring angular momentum from the Pt film to the FeGa film. The injected spin current provides energy and changes the effective temperature, thereby varying the thermal fluctuation of the magnetic moments. In a magnetic material with volume magnetostriction, the thermal fluctuation of the magnetic moments affects its volume. When the spin fluctuations change, the volume magnetostriction induces a corresponding expansion or contraction of the material. Both electrodeposited and ion-beam sputter-deposited FeGa films are investigated, and it is observed that the FeGa film exhibits SVE. The force generated by the SVE is evaluated based on the vibration amplitude at the fundamental resonant mode. This study demonstrates that the force generated by the SVE is correlated with the volume magnetostriction and the deposition process.
Yao, D.*; 松尾 衛; 横山 毅人*
Applied Physics Letters, 124(16), p.162603_1 - 162603_5, 2024/04
被引用回数：13 パーセンタイル：81.81(Physics, Applied)We propose a mechanism of spin current generation under an external electric field due to chiral phonons in a chiral-structure superconductor based on the Bogoliubov de Gennes and the Boltzmann equations.
Fe
O
川本 陽*; 吉川 貴史; 齊藤 英治; 他9名*
Applied Physics Letters, 124(13), p.132406_1 - 132406_7, 2024/03
被引用回数：8 パーセンタイル：68.36(Physics, Applied)Magnon spin currents in the ferrimagnetic garnet TbFe
O with 4
electrons were examined through the spin-Seebeck effect and neutron scattering measurements. The compound shows a magnetic compensation, where the spin-Seebeck signal reverses above and below 
= 249.5(4) K. Unpolarized neutron scattering unveils two major magnon branches with finite energy gaps, which are well explained in the framework of spin-wave theory. Their temperature dependencies and the direction of the precession motion of magnetic moments, i.e., magnon polarization, defined using polarized neutrons, explain the reversal at and decay of the spin-Seebeck signals at low temperatures. We illustrate an example that momentum- and energy-resolved microscopic information is a prerequisite to understand the magnon spin current.
-Ga
O(001)Tsai, Y. H.*; 小畠 雅明; 福田 竜生; 谷田 肇; 小林 徹; 山下 良之*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
被引用回数：4 パーセンタイル：43.27(Physics, Applied)Recently, gallium oxide (GaO) has attracted much attention as an ultra-wide bandgap semiconductor with a bandgap of about 5 eV. In order to control device properties, it is important to clarify the chemical state of dopants and doping sites. X-ray absorption near edge structure (XANES) and hard X-ray photoemission spectroscopy were used to investigate the dopant sites and chemical states of Sn in Sn-doped -GaO(001) samples. The results show that the chemical state of the Sn dopant is the Sn
oxidation state and that the bond lengths around the Sn dopant atoms are longer due to the relaxation effect after Sn dopant insertion. Comparison of experimental and simulated XANES spectra indicates that the octahedral Ga substitution site in -GaO(001) is the active site of the Sn dopant.
社本 真一; 赤津 光洋*; Chang, L.-J.*; 根本 祐一*; 家田 淳一
Applied Physics Letters, 124(11), p.112402_1 - 112402_5, 2024/03
被引用回数：2 パーセンタイル：21.99(Physics, Applied)YFeOにおける超音波注入によるマグノン励起を非弾性中性子散乱によって研究した。その結果、縦波と横波の両方で超音波注入によりマグノン励起の非弾性中性子散乱強度が増強されることがわかった。
Zhou, X.*; 福谷 克之; 他9名*
Applied Physics Letters, 124(8), p.082103_1 - 082103_7, 2024/02
被引用回数：8 パーセンタイル：68.36(Physics, Applied)Electron-doping Mottronics within correlated vanadium dioxide opens up a paradigm to abruptly regulate the Mottronic phase transitions via adjusting the 
-orbital occupancy and configuration. Nevertheless, the potential impact of high-valence elementary substitution in the hydrogen-associated Mottronic transitions of VO is yet unclear. Herein, we demonstrate the role of high-valence elementary substitution in regulating the hydrogen-triggered Mottronic transitions of VO, assisted by quantitative hydrogen analysis using the nuclear reaction analysis. Substituting vanadium with a high-valence transitional metal within doped-VO largely reduces the hydrogen incorporation compared to the intrinsic VO under the low temperature hydrogenation process. Therefore, in contrast to hydrogen-induced electron localization of intrinsic VO upon low-temperature hydrogenation, only the hydrogen-triggered metallic state is observed within the hydrogen-associated phase diagram of W
V
O, as further probed by the near-edge X-ray absorption fine structure analysis and X-ray photoelectron spectroscopy. The present work reveals the overlooked role associated with the donor substitutions that largely influences the competitive equilibrium between the two rival hydrogen-induced Mottronic transitions within VO toward either the metallic or the highly insulating phase.
松島 悠*; Zhang, Z.*; 大橋 由梨*; 畠山 紘*; Xiao, G.*; 船戸 匠*; 松尾 衛; 海住 英生*
Applied Physics Letters, 124(2), p.022404_1 - 022404_7, 2024/01
被引用回数：8 パーセンタイル：68.36(Physics, Applied)We report the discovery of a stepwise magnetic field-induced emergent magneto-inductance effect in Permalloy thin films deposited on polycarbonate substrates. This study opens up exciting avenues for advancing our understanding of emergent inductance in fundamental physics and paves the way for practical applications in flexible magnetic devices.
neutron diffraction study on the deformation behavior of the plastic inorganic semiconductor AgSWang, Y.*; Gong, W.; 川崎 卓郎; Harjo, S.; Zhang, K.*; Zhang, Z. D.*; Li, B.*
Applied Physics Letters, 123(1), p.011903_1 - 011903_6, 2023/07
被引用回数：7 パーセンタイル：49.73(Physics, Applied)Bulk AgS is a plastic inorganic semiconductor at room temperature. It exhibits a compressive strain greater than 50%, which is highly different from brittle conventional counterparts, such as silicon. Here, we present the experimental investigation of the deformation behavior in a plastic inorganic semiconductor AgS using 
neutron diffraction during compressive deformation at room and elevated temperatures. At room temperature, the lattice strain partitioning among 
-orientated grain families could be responsible for the significant work-hardening behavior in the bulk AgS with a monoclinic structure. The rapid accumulation of lattice defects and remarkable development of the deformation texture suggest that dislocation slip promotes plasticity. At 453 K, a monoclinic phase transforms into a body-centered cubic phase. A stress plateau appears at 
-4.8 MPa, followed by a rehardening state. The deformation mode of bulk AgS at the initial stage is likely attributable to the migration of silver ions, and as strain increases, it is closer to that of room temperature, leading to rehardening.
榊原 涼太郎*; Bao, J.*; Yuhara, Keisuke*; 松田 啓太*; 寺澤 知潮; 楠 美智子*; 乗松 航*
Applied Physics Letters, 123(3), p.031603_1 - 031603_4, 2023/07
被引用回数：9 パーセンタイル：59.21(Physics, Applied)ステップバンチング現象の逆であるステップアンバンチング現象について報告する。4H-SiC(0001)表面を高温でアニールすると、隣接するステップの運動の速度が異なるためにステップバンチングが生じ、数ナノメートル以上の高さのステップが生じる。本研究ではAr/H雰囲気中での水素エッチングによって得られたステップが、その後低温でアニールされると、より低い高さのステップに「アンバンチング」されることを見出した。この「束にならない」現象は、エネルギー論と動力学との間の競合の結果としてうまく説明できる。本発見は、水素エッチングによるSiCの表面平滑化のための別のアプローチを提供し、SiCパワーデバイスや二次元材料成長技術全般への応用に重要な洞察を与える可能性がある。
by monolayer hexagonal boron nitride coating for improved photo- and thermionic-cathodes山口 尚登*; 遊佐 龍之介*; Wang, G.*; Pettes, M. T.*; Liu, F.*; 津田 泰孝; 吉越 章隆; 虻川 匡司*; Moody, N. A.*; 小川 修一*
Applied Physics Letters, 122(14), p.141901_1 - 141901_7, 2023/04
被引用回数：8 パーセンタイル：54.76(Physics, Applied)単層BMをコートしたLaBの仕事関数の低減に関して報告する。hBNでコートされた領域は、非被覆あるいはグラフェンコートされたLaB(100)単結晶領域に比べて仕事関数が低下していることが、光電子顕微鏡(PEEM)および熱電子顕微鏡(TEEM)実験から分かった。グラフェンコートに比べてhBNコートされたLaB(100)では、非常に大きな仕事関数の低下が起きることが、DFT計算から定性的に分かった。計算に酸化層を考慮すると、計算と実験の間の整合性が改善された。放射光XPSによって、我々のLaB表面に酸化層が実在することを確認した。
増田 啓人*; 山根 結太*; 関 剛斎*; Raab, K.*; 土肥 昂尭*; Modak, R.*; 内田 健一*; 家田 淳一; Kl
ui, M.*; 高梨 弘毅
Applied Physics Letters, 122(16), p.162402_1 - 162402_7, 2023/04
被引用回数：4 パーセンタイル：30.23(Physics, Applied)We report current-induced magnetization switching in Pt/Co/Ir/Co/Pt multilayers with different Ir layer thicknesses (
), where the perpendicularly magnetized Co layers are coupled ferromagnetically or antiferromagnetically through an interlayer exchange coupling and are sandwiched by the Pt spin Hall layers. The domain structures formed during switching vary depending on the magnetization alignment, i.e., ferromagnetically coupled or antiferromagnetically coupled configuration. These results clarify the macroscopic picture of switching process for interlayer exchange-coupled systems. The local picture of the switching process is also examined by a numerical calculation based on a macrospin model, which reveals the switching dynamics triggered by dual spin-orbit torque for both antiferromagnetically and ferromagnetically coupled cases. The numerical calculation shows that the dual spin-orbit torque from the two Pt layers effectively acts on the two Co layers not only for the antiferromagnetically coupled case but also for the ferromagnetically coupled one. Our findings deepen the under- standing of the switching mechanism in a magnetic multilayer and provide an avenue to design spintronic devices with more efficient spin-orbit torque switching.
