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Asymmetrically optimized structure in a high-$$T_{rm c}$$ single unit-cell FeSe superconductor

深谷 有喜; Zhou, G.*; Zheng, F.*; Zhang, P.*; Wang, L.*; Xue, Q.-K.*; 社本 真一

Journal of Physics; Condensed Matter, 31(5), p.055701_1 - 055701_6, 2019/02

 被引用回数:4 パーセンタイル:26.56(Physics, Condensed Matter)



Band structures of 4$$f$$ and 5$$f$$ materials studied by angle-resolved photoelectron spectroscopy

藤森 伸一

Journal of Physics; Condensed Matter, 28(15), p.153002_1 - 153002_31, 2016/04

 被引用回数:17 パーセンタイル:61.65(Physics, Condensed Matter)

Recent remarkable progresses in angle resolved photoelectron spectroscopy (ARPES) made it possible to directly observe the band structures of 4$$f$$ and 5$$f$$ materials. In particular, ARPES with various light sources such as laser or high-energy synchrotron radiations shed light on the bulk band structures of strongly-correlated materials with the energy scales from few meV to several eV. The main purpose of the present article is to summarize the behaviors of 4$$f$$ and 5$$f$$ band structures of various rare earth and actinide materials observed by modern ARPES techniques, and understand how they can be described by various theoretical frameworks. For 4$$f$$-electron materials, ARPES studies of CeMIn$$_5$$ and YbRh$$_2$$Si$$_2$$ with various incident photon energies are summarized. For U 5$$f$$ compounds, ARPES studies of UFeGa$$_5$$, UPd$$_3$$, and URu$$_2$$Si$$_2$$ are summarized based on various ARPES studies. The present status of the field as well as possible future directions are discussed.


Theory of spin Hall magnetoresistance (SMR) and related phenomena

Chen, Y.-T.*; 高橋 三郎*; 中山 裕康*; Althammer, M.*; Goennenwein, S. T. B.*; 齊藤 英治; Bauer, G. E. W.*

Journal of Physics; Condensed Matter, 28(10), p.103004_1 - 103004_15, 2016/03

 被引用回数:45 パーセンタイル:34.55(Physics, Condensed Matter)



Phonons of Fe-based superconductor Ca$$_{10}$$Pt$$_4$$As$$_8$$(Fe$$_{1-x}$$Pt$$_x$$As)$$_{10}$$

池内 和彦*; 小林 義明*; 鈴木 一範*; 伊藤 正行*; 梶本 亮一; Bourges, P.*; Christianson, A. D.*; 中村 博樹; 町田 昌彦; 佐藤 正俊*

Journal of Physics; Condensed Matter, 27(46), p.465701_1 - 465701_7, 2015/11

 被引用回数:1 パーセンタイル:92.69(Physics, Condensed Matter)



Effect of magnetic field on positron lifetimes of Fe, Co and Ni

Li, H.; 前川 雅樹; 河裾 厚男; 谷村 直樹*

Journal of Physics; Condensed Matter, 27(24), p.246001_1 - 246001_5, 2015/06

 被引用回数:5 パーセンタイル:66.48(Physics, Condensed Matter)

Positron lifetime spectra of Fe, Co and Ni were measured under magnetic field using a $$^{22}$$Na source. Very small but distinguishable difference of positron lifetime upon magnetic field reversal was observed suggesting the existence of two bulk lifetimes associated with majority and minority spin electrons. Using two spin-dependent Fe bulk lifetimes, the difference Doppler broadening of annihilation radiation spectra between majority and minority spin electrons were also examined. Agreement between experiment and theory indicates that spin-polarized positron annihilation spectroscopy may have potential in investigation of spin-aligned electron momentum distribution.


Longitudinal spin Seebeck effect; From fundamentals to applications

内田 健一*; 石田 真彦*; 吉川 貴史*; 桐原 明宏*; 村上 朝夫*; 齊藤 英治

Journal of Physics; Condensed Matter, 26(34), p.343202_1 - 343202_15, 2014/08

 被引用回数:120 パーセンタイル:16.21(Physics, Condensed Matter)

The spin Seebeck effect refers to the generation of spin voltage as a result of a temperature gradient in ferromagnetic or ferrimagnetic materials. When a conductor is attached to a magnet under a temperature gradient, the thermally generated spin voltage in the magnet injects a spin current into the conductor, which in turn produces electric voltage owing to the spin-orbit interaction. The spin Seebeck effect is of increasing importance in spintronics, since it enables direct generation of a spin current from heat and appears in a variety of magnets ranging from metals and semiconductors to insulators. Recent studies on the spin Seebeck effect have been conducted mainly in paramagnetic metal/ferrimagnetic insulator junction systems in the longitudinal configuration in which a spin current flowing parallel to the temperature gradient is measured. This "longitudinal spin Seebeck effect" (LSSE) has been observed in various sample systems and exclusively established by separating the spin-current contribution from extrinsic artefacts, such as conventional thermoelectric and magnetic proximity effects. The LSSE in insulators also provides a novel and versatile pathway to thermoelectric generation in combination of the inverse spin-Hall effects. In this paper, we review basic experiments on the LSSE and discuss its potential thermoelectric applications with several demonstrations.


Possible method to observe the breathing mode of a magnetic domain wall in the Josephson junction

森 道康; 小椎八重 航*; 挽野 真一*; 前川 禎通

Journal of Physics; Condensed Matter, 26(25), p.255702_1 - 255702_5, 2014/06


 被引用回数:1 パーセンタイル:93.46(Physics, Condensed Matter)

A magnetic domain wall (DW) behaves as a massive particle with elasticity. Sliding and oscillation of the DW have been observed experimentally, whereas vibration of a width in the DW, "breathing mode", has not been measured so far. We theoretically propose how to observe the breathing mode by the Josephson junction having a ferromagnetic layer between superconducting electrodes. The current-voltage ($$I$$-$$V$$) curve is calculated by an equivalent circuit of the resistively shunted junction model. The breathing mode is identified by stepwise structures in the $$I$$-$$V$$ curve, which appear at the voltages $$V$$=$$n(hbar/2e$$)$$omega$$ with the fundamental constant $$hbar/e$$, integer number $$n$$, and the frequency of the breathing mode $$omega$$.


Weak itinerant antiferromagnetism in PuIn$$_3$$ explored using $$^{115}$$In nuclear quadrupole resonance

中堂 博之; Koutroulakis, G.*; 安岡 弘志; Bauer, E. D.*; Tobash, P. H.*; Mitchell, J. N.*; Thompson, J. D.*

Journal of Physics; Condensed Matter, 26(3), p.036001_1 - 036001_5, 2014/01

 被引用回数:4 パーセンタイル:74.11(Physics, Condensed Matter)

PuIn$$_3$$における$$^{115}$$In NQR測定の結果について報告する。$$^{115}$$Inの核スピン$$I$$=9/2に期待される4本のNQR共鳴線のうちの3本の共鳴線を観測した。20Kにおいて、それらの共鳴線は等間隔であり、そこからNQR周波数$$nu_{rm Q}=10.45$$MHzと電場勾配の非対称パラメータの$$eta=0$$が導かれた。14Kにおいて、NQR共鳴線の形状と核スピン緩和率1/$$T_1$$は反強磁性転移により変化を生じる。14K以下において、NQRスペクトルより見積もられた内部交番磁化$$M_{rm Q}(T)$$と1/$$T_1$$の温度依存性はスピン揺らぎのSCR理論によりよく説明される。さらに、$$T_1T$$$$M_{rm Q}(T)/M_{rm Q}(0)$$はSCR理論から予言される通りに比例している。これらの結果はPuIn$$_3$$が弱い反強磁性体、すなわち有限温度において反強磁性波数近傍のスピン揺らぎが物性を支配している証拠である。


Quadrupole effects in tetragonal crystals PrCu$$_2$$Si$$_2$$ and DyCu$$_2$$Si$$_2$$

三本 啓輔*; 後藤 沙織*; 根本 祐一*; 赤津 光洋*; 後藤 輝孝*; Dung, N. D.*; 松田 達磨; 芳賀 芳範; 竹内 徹也*; 杉山 清寛*; et al.

Journal of Physics; Condensed Matter, 25(29), p.296002_1 - 296002_8, 2013/07

 被引用回数:1 パーセンタイル:93.35(Physics, Condensed Matter)

We have investigated quadrupole effects in tetragonal crystals of PrCu$$_2$$Si$$_2$$ and DyCu$$_2$$Si$$_2$$ by means of low-temperature ultrasonic measurements. The elastic constant C$$_{44}$$ of PrCu$$_2$$Si$$_2$$ exhibits pronounced softening below 70 K, which is described in terms of a quadrupole susceptibility for a doublet ground state.


Perpendicular magnetic anisotropy with enhanced orbital moments of Fe adatoms on a topological surface of Bi$$_2$$Se$$_3$$

Ye, M.*; 黒田 健太*; 竹田 幸治; 斎藤 祐児; 岡本 和晃*; Zhu, S.-Y.*; 白井 開渡*; 宮本 幸治*; 有田 将司*; 仲武 昌史*; et al.

Journal of Physics; Condensed Matter, 25(23), p.232201_1 - 232201_5, 2013/06

 被引用回数:10 パーセンタイル:51.34(Physics, Condensed Matter)

トポロジカル絶縁体に磁性元素を入れると絶縁体表面に対して垂直方向に強磁性が発現するという理論研究があり、その実現は新しいスピントロにクス技術への足がかりになるものと期待されている。本研究では、トポロジカル絶縁体Bi$$_2$$Se$$_3$$の表面にFeを蒸着し、その磁性をFe L$$_{2,3}$$吸収端における軟X線磁気円二色性で、電子状態を角度分解光電子分光を用いて調べた。磁気円二色性実験ではFeの膜厚依存性、試料表面に対する角度依存性測定も行った。その結果、いずれのFe膜厚(0.013-0.9ML)においても強磁性発現は確認できなかったものの、試料表面に垂直方向に磁気モーメントが向く強い磁気異方性を持った常磁性状態が確認された。また軌道磁気モーメントがFe膜厚の小さい試料において増大し、スピン磁気モーメントと軌道磁気モーメントの比率が強い膜厚依存性を示すこともわかった。この結果はトポロジカル絶縁体に対する磁性元素の量を調節することにより、磁性及び量子輸送現象を制御できる可能性を示すものである。


Solution softening in magnesium alloys; The Effect of solid solutions on the dislocation core structure and nonbasal slip

都留 智仁; 宇田川 豊; 山口 正剛; 板倉 充洋; 蕪木 英雄; 加治 芳行

Journal of Physics; Condensed Matter, 25(2), p.022202_1 - 022202_5, 2013/01

 被引用回数:48 パーセンタイル:11.14(Physics, Condensed Matter)



Observation of a pressure-induced As-As hybridization associated with a change in the electronic state of Fe in the tetragonal phase of EuFe$$_2$$As$$_2$$

小林 寿夫*; 池田 修悟*; 阪口 友唯*; 依田 芳卓*; 中村 博樹; 町田 昌彦

Journal of Physics; Condensed Matter, 25(2), p.022201_1 - 022201_6, 2013/01

 被引用回数:8 パーセンタイル:55.03(Physics, Condensed Matter)



The Temperature dependence of Cu$$_{2}$$O formation on a Cu(110) surface with an energetic O$$_{2}$$ molecular beam

橋之口 道宏*; 吉越 章隆; 寺岡 有殿; 岡田 美智雄*

Journal of Physics; Condensed Matter, 24(39), p.395007_1 - 395007_8, 2012/10

 被引用回数:4 パーセンタイル:76.33(Physics, Condensed Matter)

We report a study of the surface temperature (Ts) dependence of Cu$$_{2}$$O formation on a Cu(110) surface induced by a hyperthermal O$$_{2}$$ molecular beam (HOMB), using X-ray photoemission spectroscopy in conjunction with synchrotron radiation. From the Ts dependence of the O uptake curves, the direct dissociative adsorption process mainly contributes to the formation of the p(2$$times$$1)-O structure with an O coverage of 0.5 ML for 2.2 eV HOMB incidence. On the other hand, the rate of oxidation at the coverage larger than 0.5 ML, particularly in Cu$$_{2}$$O formation, strongly depends on the Ts. Thicker Cu$$_{2}$$O islands were found in homogeneously at 400 and 500 K, suggesting the dominant role of the migration of Cu atoms in the Cu$$_{2}$$O formations on the Cu(110) surface.


A Theoretical study of the reactivity of Cu$$_{2}$$O(111) surfaces; The Case of NO dissociation

岸 浩史*; Padama, A. A. B.*; Arevalo, R. L.*; Moreno, J. L. V.*; 笠井 秀明*; 谷口 昌司*; 上西 真里*; 田中 裕久*; 西畑 保雄

Journal of Physics; Condensed Matter, 24(26), p.262001_1 - 262001_5, 2012/07

 被引用回数:6 パーセンタイル:66.58(Physics, Condensed Matter)



NO dissociation on Cu(111) and Cu$$_{2}$$O(111) surfaces; A Density functional theory based study

Padama, A. A. B.*; 岸 浩史*; Arevalo, R. L.*; Moreno, J. L. V.*; 笠井 秀明*; 谷口 昌司*; 上西 真里*; 田中 裕久*; 西畑 保雄

Journal of Physics; Condensed Matter, 24(17), p.175005_1 - 175005_6, 2012/05

 被引用回数:28 パーセンタイル:22.01(Physics, Condensed Matter)



X-ray fluorescence holography

林 好一*; 八方 直久*; 細川 伸也*; Hu, W.; 松下 智裕*

Journal of Physics; Condensed Matter, 24(9), p.093201_1 - 093201_15, 2012/03

 被引用回数:56 パーセンタイル:43.36(Physics, Condensed Matter)

X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy.


Magnetic anisotropy and spin-glass behavior in single crystalline U$$_2$$PdSi$$_3$$

Li, D. X.*; 木村 昭裕*; 芳賀 芳範; 二森 茂樹*; 四竈 樹男*

Journal of Physics; Condensed Matter, 23(7), p.076003_1 - 076003_7, 2011/02

 被引用回数:10 パーセンタイル:52.15(Physics, Condensed Matter)

We present the magnetic and transport properties of single crystalline U$$_2$$PdSi$$_3$$ measured with the magnetic field applied along two typical crystallographic directions. For both directions, a spin-glass state is confirmed to form at low temperature with the same spin freezing temperature 11.5 K, initial frequency shift 0.023 and activation energy 90.15 K in zero field. Strong anisotropy in magnetic and transport behavior is found to be a significant feature of U$$_2$$PdSi$$_3$$. The usual ferromagnetic-like anomaly in ac susceptibility and dc magnetization curves around 71 K is observed for $$H parallel c$$.


Electronic and local structures of BiFeO$$_3$$ films

米田 安宏; 坂本 渉*

Journal of Physics; Condensed Matter, 23(1), p.015902_1 - 015902_5, 2011/01

 被引用回数:12 パーセンタイル:46.6(Physics, Condensed Matter)



Orientation dependence of Pd growth on Au electrode surfaces

高橋 正光; 田村 和久; 水木 純一郎; 近藤 敏啓*; 魚崎 浩平*

Journal of Physics; Condensed Matter, 22(47), p.474002_1 - 474002_9, 2010/12

 被引用回数:13 パーセンタイル:43.98(Physics, Condensed Matter)

Thin Pd films which were electrochemically grown on Au(111) and Au(001) electrodes have been investigated by surface X-ray scattering. Comparison of Pd/Au(111) and Pd/Au(001) growth modes shows similarity in the first layer deposition. On Au(111) and Au(001) substrates, Pd follows the crystal structure of the substrates and forms a pseudomorphic monolayer. Beyond 2 ML, however, Pd films grown on Au(111) are relaxed, although there are still pseudomorphic layers at the interface. In contrast, Pd films on Au(001) continue to grow pseudomorphically over 10 ML. The difference in the growth mode between (111) and (001) surfaces is not ascribable only to anisotropy in the elasticity of the film. The relationship between a growing surface and an allowed gliding plane in misfit dislocations is presented as a crucial factor determining the critical thickness of the film.


Epitaxial growth of largely mismatched crystals on H-terminated Si (111) surfaces

朝岡 秀人

Journal of Physics; Condensed Matter, 22(47), p.474007_1 - 474007_7, 2010/12

 被引用回数:0 パーセンタイル:100(Physics, Condensed Matter)


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