※ 半角英数字
 年 ~ 
検索結果: 114 件中 1件目~20件目を表示


Initialising ...



Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...



Evidence for magnon-phonon coupling in the topological magnet Cu$$_{3}$$TeO$$_{6}$$

Bao, S.*; Cai, Z.*; Si, W.*; Wang, W.*; Wang, X.*; Shangguan, Y.*; Ma, Z.*; Dong, Z.-Y.*; 梶本 亮一; 池内 和彦*; et al.

Physical Review B, 101(21), p.214419_1 - 214419_8, 2020/06

 被引用回数:0 パーセンタイル:100(Materials Science, Multidisciplinary)

We perform thermodynamic and inelastic neutron scattering (INS) measurements to study the lattice dynamics (phonons) of a cubic collinear antiferromagnet Cu$$_{3}$$TeO$$_{6}$$ which hosts topological spin excitations (magnons). While the specific heat and thermal conductivity results show that the thermal transport is dominated by phonons, the deviation of the thermal conductivity from a pure phononic model indicates that there is a strong coupling between magnons and phonons. In the INS measurements, we find a mode in the excitation spectra at 4.5 K, which exhibits a slight downward dispersion around the Brillouin zone center. This mode disappears above the N$'{e}$el temperature and thus cannot be a phonon. Furthermore, the dispersion is distinct from that of a magnon. Instead, it can be explained by the magnon-polaron mode, collective excitations resulting from the hybridization between magnons and phonons. We consider the suppression of the thermal conductivity and emergence of the magnon-polaron mode to be evidence for magnon-phonon coupling in Cu$$_{3}$$TeO$$_{6}$$.


The $$f$$-electron state of the heavy fermion superconductor NpPd$$_5$$Al$$_2$$ and the isostructural family

目時 直人; Aczel, A. A.*; 青木 大*; Chi, S.*; Fernandez-Baca, J. A.*; Griveau, J.-C.*; 萩原 正人*; Hong, T.*; 芳賀 芳範; 池内 和彦*; et al.

JPS Conference Proceedings (Internet), 30, p.011123_1 - 011123_6, 2020/03



Strong local moment antiferromagnetic spin fluctuations in V-doped LiFeAs

Xu, Z.*; Dai, G.*; Li, Y.*; Yin, Z.*; Rong, Y.*; Tian, L.*; Liu, P.*; Wang, H.*; Xing, L.*; Wei, Y.*; et al.

npj Quantum Materials (Internet), 5(1), p.11_1 - 11_7, 2020/02

 被引用回数:1 パーセンタイル:100(Materials Science, Multidisciplinary)

We use neutron scattering to study Vanadium (hole)-doped LiFe$$_{1-x}$$V$$_{x}$$As. In the undoped state, LiFeAs exhibits superconductivity at $$T_mathrm{c} = 18$$ K and transverse incommensurate spin excitations similar to electron overdoped iron pnictides. Upon Vanadium doping to form LiFe$$_{0.955}$$V$$_{0.045}$$, the transverse incommensurate spin excitations in LiFeAs transform into longitudinally elongated ones in a similar fashion to that of potassium (hole)-doped Ba$$_{0.7}$$K$$_{0.3}$$Fe$$_{2}$$As$$_{2}$$ but with dramatically enhanced magnetic scattering and elimination of superconductivity. This is different from the suppression of the overall magnetic excitations in hole-doped BaFe$$_{2}$$As$$_{2}$$ and the enhancement of superconductivity near optimal hole doping. These results are consistent with density function theory plus dynamic mean field theory calculations, suggesting that Vanadium doping in LiFeAs may induce an enlarged effective magnetic moment $$S_mathrm{eff}$$ with a spin crossover ground state arising from the inter-orbital scattering of itinerant electrons.


Q dependence of magnetic resonance mode on FeTe$$_{0.5}$$Se$$_{0.5}$$ studied by inelastic neutron scattering

石角 元志*; 樹神 克明; 梶本 亮一; 中村 充孝; 稲村 泰弘; 池内 和彦*; Ji, S.*; 新井 正敏*; 社本 真一

Condensed Matter (Internet), 4(3), p.69_1 - 69_10, 2019/09



Quantum dynamics of hydrogen in the iron-based superconductor LaFeAsO$$_{0.9}$$D$$_{0.1}$$ measured with inelastic neutron spectroscopy

山浦 淳一*; 平賀 晴弘*; 飯村 壮史*; 村場 善行*; Bang, J.*; 池内 和彦*; 中村 充孝; 稲村 泰弘; 本田 孝志*; 平石 雅俊*; et al.

Physical Review B, 99(22), p.220505_1 - 220505_6, 2019/06

 被引用回数:1 パーセンタイル:71.33(Materials Science, Multidisciplinary)



Study on use of superconducting magnet and first inelastic neutron scattering experiment under magnetic field at 4SEASONS spectrometer

梶本 亮一; 石角 元志*; 吉良 弘*; 金子 耕士; 中村 充孝; 蒲沢 和也*; 稲村 泰弘; 池内 和彦*; 飯田 一樹*; 村井 直樹; et al.

Physica B; Condensed Matter, 556, p.26 - 30, 2019/03

 被引用回数:2 パーセンタイル:54.14(Physics, Condensed Matter)

Magnets are important for studying magnetism and are commonly used as sample environment devices of neutron scattering instruments. However, the use of magnets was prevented at the time-of-flight direct-geometry neutron spectrometer 4SEASONS in Materials and Life Science Experimental Facility (MLF) at J-PARC, because the instrument is surrounded by iron components, and it is equipped with a piece of equipment operated with magnetic bearings. In the present work, we investigate the influence of stray magnetic fields from a superconducting magnet which is shared among neutron scattering instruments in MLF. Based on the investigation, we modified 4SEASONS such that it can be used with the magnet. Finally, we successfully performed the first inelastic neutron scattering experiments with applied magnetic fields using this sample environment.


Performances of oscillating radial collimator for the Fermi chopper spectrometer 4SEASONS at J-PARC

中村 充孝; 神原 理*; 飯田 一樹*; 梶本 亮一; 蒲沢 和也*; 池内 和彦*; 石角 元志*; 青山 和弘*

Physica B; Condensed Matter, 551, p.480 - 483, 2018/12

 被引用回数:1 パーセンタイル:86.6(Physics, Condensed Matter)



Local structure study of the iron-based systems of BaFe$$_2$$As$$_2$$ and LiFeAs by X-ray PDF and XAFS analyses

Li, S.*; 豊田 真幸*; 小林 義明*; 伊藤 正行*; 池内 和彦*; 米田 安宏; 大谷 彬*; 松村 大樹; 浅野 駿*; 水木 純一郎*; et al.

Physica C, 555, p.45 - 53, 2018/12

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



Gapless magnetic excitation in a heavily electron-doped antiferromagnetic phase of LaFeAsO$$_{0.5}$$D$$_{0.5}$$

玉造 博夢*; 平賀 晴弘*; 池内 和彦*; 飯村 壮史*; 村場 善行*; 中村 充孝; 佐賀山 基*; 山浦 淳一*; 村上 洋一*; 倉本 義夫*; et al.

Physical Review B, 98(17), p.174415_1 - 174415_6, 2018/11


 被引用回数:1 パーセンタイル:86.6(Materials Science, Multidisciplinary)



Al-impurity-induced magnetic excitations in heavily over-doped La$$_{1.7}$$Sr$$_{0.3}$$Cu$$_{0.95}$$Al$$_{0.05}$$O$$_{4}$$

池内 和彦*; 中島 健次; 河村 聖子; 梶本 亮一; 脇本 秀一; 鈴木 謙介*; 藤田 全基*

AIP Advances (Internet), 8(10), p.101318_1 - 101318_5, 2018/10

 被引用回数:0 パーセンタイル:100(Nanoscience & Nanotechnology)



Neutron inelastic scattering study of the $$f$$-electron states in NdPd$$_5$$Al$$_2$$

目時 直人; 山内 宏樹; 鈴木 博之*; 北澤 英明*; 蒲沢 和也*; 池内 和彦*; 梶本 亮一; 中村 充孝; 稲村 泰弘

Journal of the Physical Society of Japan, 87(8), p.084708_1 - 084708_7, 2018/08

 被引用回数:5 パーセンタイル:33.27(Physics, Multidisciplinary)

$$f$$電子化合物NdPd$$_5$$Al$$_2$$の中性子散乱による研究を行った。0K, 35.4K, 88.3K, 101.5K, and 198.8Kの結晶場レベルを励起スペクトルから明らかにした。$$Gamma_6$$基底状態は主として$$J_z=pm9/2$$の軌道によって構成され、これが大きな負の$$B_{20}=-1.4$$Kと一軸異方性を生じる。結晶場から計算された磁気モーメント, 帯磁率, 磁化曲線, 比熱は実験をよく説明する。CePd$$_5$$Al$$_2$$やPrPd$$_5$$Al$$_2$$と共通した電荷分布の存在は同じ構造を持つアクチノイド化合物においても局在的な性質が重要で、UPd$$_5$$Al$$_2$$の局在5$$f$$電子状態やNpPd$$_5$$Al$$_2$$の重い電子系超伝導にその価数の不安定性が重要な役割をすることを示している。


Status report of the chopper spectrometer 4SEASONS

梶本 亮一; 中村 充孝; 稲村 泰弘; 蒲沢 和也*; 池内 和彦*; 飯田 一樹*; 石角 元志*; 村井 直樹; 吉良 弘*; 中谷 健; et al.

Journal of Physics; Conference Series, 1021(1), p.012030_1 - 012030_6, 2018/06

 被引用回数:2 パーセンタイル:9.58

4SEASONS is a medium-resolution thermal neutron chopper spectrometer in the Materials and Life Science Experimental Facility (MLF) at J-PARC. Although 4SEASONS is routinely used for many experiments by internal and external users, upgrading and maintenance work is still underway. This paper reviews the recent improvements of the instrument.


Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe$$_{4}$$As$$_{4}$$

Xie, T.*; Wei, Y.*; Gong, D.*; Fennell, T.*; Stuhr, U.*; 梶本 亮一; 池内 和彦*; Li, S.*; Hu, J.*; Luo, H.*

Physical Review Letters, 120(26), p.267003_1 - 267003_7, 2018/06

 被引用回数:12 パーセンタイル:17.42(Physics, Multidisciplinary)

We report an inelastic neutron scattering study on the spin resonance in the bilayer iron-based superconductor CaKFe$$_4$$As$$_4$$. In contrast to its quasi-two-dimensional electron structure, three strongly $$L$$-dependent modes of spin resonance are found below $$T_c$$ = 35 K. The mode energies are below and linearly scale with the total superconducting gaps summed on the nesting hole and electron pockets, essentially in agreement with the results in cuprate and heavy fermion superconductors. This observation supports the sign-reversed Cooper-pairing mechanism under multiple pairing channels and resolves the long-standing puzzles concerning the broadening and dispersive spin resonance peak in iron pnictides. More importantly, the triple resonant modes can be classified into odd and even symmetries with respect to the distance of Fe-Fe planes within the Fe-As bilayer unit. Thus, our results closely resemble those in the bilayer cuprates with nondegenerate spin excitations, suggesting that these two high-$$T_c$$ superconducting families share a common nature.


Magnetic excitations in the orbital disordered phase of MnV$$_2$$O$$_4$$

松浦 慧介*; 佐賀山 基*; 上原 周*; 新居 陽一*; 梶本 亮一; 蒲沢 和也*; 池内 和彦*; Ji, S.*; 阿部 伸行*; 有馬 孝尚*

Physica B; Condensed Matter, 536, p.372 - 376, 2018/05

 被引用回数:1 パーセンタイル:86.6(Physics, Condensed Matter)

We have investigated the temperature dependence of magnetic dynamics in a spinel-type vanadium oxide MnV$$_2$$O$$_4$$ by inelastic neutron scattering. The scattering intensity of excitation around 20 meV disappears in the collinear intermediate-temperature cubic-ferrimagnetic phase, which reveals that this excitation should be peculiar to the orbital ordered phase. We have found a weakly dispersive mode emergent from a non-integer wavevector $$(1.4,1.4,0)$$ at 56 K, which lies in the cubic-ferrimagnetic phase between non-coplanar ferrimagnetic and paramagnetic phases. This indicates that the probable presence of an incommensurate instability in the simple collinear structure.


Detailed study of the structure of the low-energy magnetic excitations in overdoped La$$_{1.75}$$Sr$$_{0.25}$$CuO$$_{4}$$

池内 和彦*; 菊地 龍弥*; 中島 健次; 梶本 亮一; 脇本 秀一; 藤田 全基*

Physica B; Condensed Matter, 536, p.717 - 719, 2018/05

 被引用回数:1 パーセンタイル:86.6(Physics, Condensed Matter)

銅酸化物高温超伝導体の過剰ドープ領域における低エネルギーの磁気励起の構造の詳細を調べるために、我々は、La$$_{1.75}$$Sr$$_{0.25}$$CuO$$_{4}$$の中性子非弾性散乱実験を行った。過去に報告されたように、非整合な磁気相関に対応した$$Q_{rm tet}$$ = (0.5 $$pm$$ $$delta$$, 0.5)/(0.5, 0.5 $$pm$$ $$delta$$)を中心とした磁気励起を明瞭に観測した。それに加えて、$$Q_{rm tet}=(0.5, 0.5)$$を中心とした円環状の励起も観測された。円環の半径($$r$$=0.109)は、磁気相関の非整合性($$delta$$=0.118)より小さい。このことは、円環状の磁気励起は非整合な磁気相関とはその原因を異にしていることを示唆している。La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$の磁気励起はこのように2種類の励起を持つことが示唆される。


Fe-impurity-induced magnetic excitations in heavily over-doped La$$_{1.7}$$Sr$$_{0.3}$$Cu$$_{0.95}$$Fe$$_{0.05}$$O$$_{4}$$

池内 和彦*; 菊地 龍弥*; 中島 健次; 梶本 亮一; 脇本 秀一; 藤田 全基*

Journal of Physics; Conference Series, 969(1), p.012024_1 - 012024_5, 2018/04

 被引用回数:1 パーセンタイル:23.99

Inelastic neutron scattering experiments were performed to investigate the effect of Fe substitution on the magnetic excitation spectra in a heavily hole-doped cuprate system La$$_{1.7}$$Sr$$_{0.3}$$Cu$$_{0.95}$$Fe$$_{0.05}$$O$$_{4}$$. Well-defined low-energy magnetic excitations, associated with a static magnetic order, were observed at the incommensurate (IC) positions. The incommensurability of 0.144 (r.l.u) was larger than that of $$sim$$0.125 (r.l.u) in LSCO with $$x$$ = 0.25, suggesting an increase of incommensurability by Fe substitution. In addition to the obvious effect on IC excitations, we show the emergence of ring-shaped magnetic excitations by Fe-substitution. These results are incompatible with a simple pinning scenario of the stripe order, which is characterized by local spin correlations. The metallic aspect of the low-energy part of the magnetic excitation, which underlies high-temperature superconductivity in over-doped cuprate systems, would be enhanced/induced by Fe substitution.


Spin-orbital correlated dynamics in the spinel-type vanadium oxide MnV$$_{2}$$O$$_{4}$$

松浦 慧介*; 佐賀山 基*; 上原 周*; 新居 陽一*; 梶本 亮一; 蒲沢 和也*; 池内 和彦*; Ji, S.*; 阿部 伸行*; 有馬 孝尚*

Physical Review Letters, 119(1), p.017201_1 - 017201_6, 2017/07

 被引用回数:6 パーセンタイル:36.07(Physics, Multidisciplinary)

We investigate the magnetic dynamics in the spinel-type vanadium oxide MnV$$_2$$O$$_4$$. Inelastic neutron scattering around 10 meV and a Heisenberg model analysis have revealed that V$$^{3+}$$ spin-wave modes exist at a lower-energy region than previously reported. The scattering around 20 meV cannot be reproduced with the spin-wave analysis. We propose that this scattering could originate from the spin-orbital coupled excitation. This scattering is most likely attributable to V$$^{3+}$$ spin-wave modes, entangled with the orbital hybridization between $$t_{2g}$$ orbitals.


Spin excitations in optimally P-doped BaFe$$_2$$(As$$_{0.7}$$P$$_{0.3}$$)$$_2$$ superconductor

Hu, D.*; Yin, Z.*; Zhang, W.*; Ewings, R. A.*; 池内 和彦*; 中村 充孝; Roessli, B.*; Wei, Y.*; Zhao, L.*; Chen, G.*; et al.

Physical Review B, 94(9), p.094504_1 - 094504_7, 2016/09


 被引用回数:9 パーセンタイル:46.15(Materials Science, Multidisciplinary)

最適Pドープされた超伝導体BaFe$$_2$$(As$$_{0.7}$$P$$_{0.3}$$)$$_2$$ (T$$_c$$=30K)におけるスピン励起の温度及びエネルギー依存性が非弾性中性子散乱実験を使って調べられた。我々の実験結果は密度汎関数理論や動的平均場理論で予想される計算結果と矛盾しておらず、BaFe$$_2$$(As$$_{0.7}$$P$$_{0.3}$$)$$_2$$における平均プニクトゲン高さの減少が、電子相関の強さを弱め、磁気励起の有効バンド幅の増加に寄与することを示唆している。


Spin excitations in hole-overdoped iron-based superconductors

堀金 和正*; 木方 邦宏*; 藤田 慧*; 梶本 亮一; 池内 和彦*; Ji, S.*; 秋光 純*; Lee, C. H.*

Scientific Reports (Internet), 6, p.33303_1 - 33303_6, 2016/09

 被引用回数:10 パーセンタイル:29.12(Multidisciplinary Sciences)

We report a study on the spin fluctuations of the hole-overdoped iron-based superconductors Ba$$_{1-x}$$K$$_x$$Fe$$_2$$As$$_2$$ ($$x$$ = 0.5 and 1.0; $$T_c$$ = 36 K and 3.4 K, respectively) over the entire Brillouin zone using inelastic neutron scattering. We find that their spin spectra consist of spin wave and chimney-like dispersions. The chimney-like dispersion can be attributed to the itinerant character of magnetism. The band width of the spin wave-like dispersion is almost constant from the non-doped to optimum-doped region, which is followed by a large reduction in the overdoped region. This suggests that the superconductivity is suppressed by the reduction of magnetic exchange couplings, indicating a strong relationship between magnetism and superconductivity in iron-based superconductors.


Observation of momentum-resolved charge fluctuations proximate to the charge-order phase using resonant inelastic X-ray scattering

吉田 雅洋*; 石井 賢司; 中 惇*; 石原 純夫*; Jarrige, I.*; 池内 和彦*; 村上 洋一*; 工藤 一貴*; 小池 洋二*; 永田 知子*; et al.

Scientific Reports (Internet), 6, p.23611_1 - 23611_8, 2016/03

 被引用回数:0 パーセンタイル:100(Multidisciplinary Sciences)

In strongly correlated electron systems, enhanced fluctuations in the proximity of the ordered states of electronic degrees of freedom often induce anomalous electronic properties such as unconventional superconductivity. While spin fluctuations in the energy-momentum space have been studied widely using inelastic neutron scattering, other degrees of freedom, i.e., charge and orbital, have hardly been explored thus far. Here, we use resonant inelastic X-ray scattering to observe charge fluctuations proximate to the charge-order phase in transition metal oxides. In the two-leg ladder of Sr$$_{14-x}$$Ca$$_x$$Cu$$_{24}$$O$$_{41}$$, charge fluctuations are enhanced at the propagation vector of the charge order ($$mathbf{q}_mathrm{CO}$$) when the order is melted by raising the temperature or by doping holes. In contrast, charge fluctuations are observed not only at $$mathbf{q}_mathrm{CO}$$ but also at other momenta in a geometrically frustrated triangular bilayer lattice of LuFe$$_2$$O$$_4$$. The observed charge fluctuations have a high energy ($$sim$$ 1 eV), suggesting that the Coulomb repulsion between electrons plays an important role in the formation of the charge order.

114 件中 1件目~20件目を表示