Coexistence of magnetoelectric and antiferroelectric-like orders in MnTaO

木村 健太*; 八木 直輝*; 長谷川 舜介*; 萩原 雅人; 三宅 厚志*; 徳永 将史*; Cao, H.*; 益田 隆嗣*; 木村 剛*

Inorganic Chemistry, 60(20), p.15078 - 15084, 2021/10

https://doi.org/10.1021/acs.inorgchem.1c02461

In materials showing a linear magnetoelectric (ME) effect, unconventional functionalities can be anticipated such as electric control of magnetism and nonreciprocal optical responses. Thus, the search of new linear ME materials is of interest in materials science. Here, using a recently proposed design principle of linear ME materials, which is based on the combination of local structural asymmetry and collinear antiferromagnetism, we demonstrate that an anion-deficient fluorite derivative MnTaO is a new linear ME material. This is evidenced by the onset of magnetic-field-induced electric polarization in its collinear antiferromagnetic phase below = 24 K. Furthermore, we also find an antiferroelectric-like phase transition at = 55 K, which is attributable to an off-center displacement of magnetic Mn ions. The present study shows that MnTaO is a rare material that exhibits both ME and antiferroelectric-like transitions. Thus, MnTaO may provide an opportunity to investigate the physics associated with complicated interactions between magnetic (spin) and electric dipole degrees of freedom.

Spin excitations of the =1/2 one-dimensional Ising-like antiferromagnet BaCoVO in transverse magnetic fields

奥谷 顕*; 大西 弘明; 木村 尚次郎*; 竹内 徹也*; 木田 孝則*; 森 道康; 三宅 厚志*; 徳永 将史*; 金道 浩一*; 萩原 政幸*

Journal of the Physical Society of Japan, 90(4), p.044704_1 - 044704_9, 2021/04

https://doi.org/10.7566/JPSJ.90.044704

The high-field multifrequency electron spin resonance (ESR), the magnetization, and the specific heat of single crystals of BaCoVO (a quasi-one-dimensional Ising-like antiferromagnet with ) were measured in two different transverse magnetic fields: and . A softening of the lowest ESR mode was observed near the saturation field of the magnetization around 40 T in , whereas it occurs around 10 T in , far below the saturation field. These observations were reproduced by numerical calculations using the density-matrix renormalization group methods, including the staggered magnetic fields induced by a uniform external magnetic field and the interchain magnetic exchange interaction. We found that the directional dependence of the lowest mode originates mainly from the remarkable angular dependence of the induced magnetic field. The interchain interaction is also quantitatively important for reproducing the experimental results. The directional dependence of the lowest mode is demonstrated by the particle-hole excitation of spinons using the Jordan-Wigner transformation.

Magnetic structures and quadratic magnetoelectric effect in LiNiPO beyond 30 T

Fogh, E.*; 木原 工*; Toft-Petersen, R.*; Bartkowiak, M.*; 鳴海 康雄*; Prokhnenko, O.*; 三宅 厚志*; 徳永 将史*; 及川 健一; Srensen, M. K.*; et al.

Physical Review B, 101(2), p.024403_1 - 024403_12, 2020/01

https://doi.org/10.1103/PhysRevB.101.024403

Neutron diffraction with static and pulsed magnetic fields is used to directly probe the magnetic structures in LiNiPO up to 25 T and 42 T, respectively. By combining these results with magnetometry and electric polarization measurements under pulsed fields, the magnetic and magnetoelectric phases are investigated up to 56 T applied along the easy axis. In addition to the already known transitions at lower fields, three new ones are reported at 37.6, 39.4, and 54 T. Ordering vectors are identified with Q = (0, , 0) in the interval 37.6 - 39.4 T and Q = (0, 0, 0) in the interval 39.4 - 54 T. A quadratic magnetoelectric effect is discovered in the Q= (0, 0, 0) phase and the field dependence of the induced electric polarization is described using a simple mean-field model. The observed magnetic structure and magnetoelectric tensor elements point to a change in the lattice symmetry in this phase. We speculate on the possible physical mechanism responsible for the magnetoelectric effect in LiNiPO.

Magnetic field induced phenomena in UIrGe in fields applied along the axis

Pospil, J.*; 芳賀 芳範; 小濱 芳允*; 三宅 厚志*; 神戸 振作; 立岩 尚之; Valika, M.*; Proschek, P.*; Prokleka, J.*; Sechovsk, V.*; et al.

Physical Review B, 98(1), p.014430_1 - 014430_7, 2018/07

https://doi.org/10.1103/PhysRevB.98.014430

The metamagnetic transition between the antiferromagnetic and paramagnetic state in UIrGe has been studied at various temperatures by magnetization, heat capacity, and magnetocaloric effect measurements on a single crystal in static and pulsed magnetic fields applied along the orthorhombic axis. The first-order transition is accompanied by a dramatic increase of the Sommerfeld coefficient. A tentative scenario explaining these anomalies by antiferromagnetic correlations or short-range order in the paramagnetic state is discussed.

Nondestructive elemental depth-profiling analysis by muonic X-ray measurement

二宮 和彦*; 久保 謙哉*; 長友 傑*; 髭本 亘; 伊藤 孝; 河村 成肇*; Strasser, P.*; 下村 浩一郎*; 三宅 康博*; 鈴木 栄男*; et al.

Analytical Chemistry, 87(9), p.4597 - 4600, 2015/05

https://doi.org/10.1021/acs.analchem.5b01169

Elemental analysis of materials is fundamentally important to science and technology. Many elemental analysis methods have been developed, but three-dimensional nondestructive elemental analysis of bulk materials has remained elusive. Recently, we developed a nondestructive depth-profiling elemental analysis method after a decade of research. This new method utilizes a new type of probe; a negative muon particle and high-energy muonic X-rays emitted after the muon stops in a material. We performed elemental depth profiling on an old Japanese gold coin (Tempo-Koban) using a low-momentum negative muon beam and successfully determined that the Au concentration in the coin gradually decreased with depth over a micrometer length scale.

Field-induced phenomena in ferromagnetic superconductors UCoGe and URhGe

青木 大*; Taupin, M.*; Paulsen, C.*; Hardy, F.*; Taufour, V.*; 小手川 恒*; Hassinger, E.*; Malone, L.*; 松田 達磨; 三宅 厚志*; et al.

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB002_1 - SB002_6, 2012/12

https://doi.org/10.1143/JPSJS.81SB.SB002

We review our recent studies on ferromagnetic superconductors, UGe2, URhGe, and UCoGe. We focus on experimental results of URhGe and UCoGe in which the superconductivity occurs already at ambient pressure. The huge upper critical field on UCoGe for the field along the hard magnetization axis (-axis) is confirmed by the AC susceptibility measurements by the fine tuning of field angle. Contrary to the huge along the hard-magnetization axis, along the easy-magnetization axis (-axis) is relatively small in value. However, the initial slope of , namely / (0) both in UCoGe and in URhGe indicates the large value, which can be explained by the magnetic domain effect detected in the magnetization measurements. The specific heat measurements using a high quality single crystal of UCoGe demonstrate the bulk superconductivity, which is extended under magnetic field for the field along -axis.

Properties of ferromagnetic superconductors

青木 大*; Hardy, F.*; 三宅 厚志*; Taufour, V.*; 松田 達磨; Flouquet, J.*

Comptes Rendus Physique, 12(5-6), p.573 - 583, 2011/06

https://doi.org/10.1016/j.crhy.2011.04.007

Thanks to the discovery in the last decade of three uranium ferromagnetic superconductors, UGe, URhGe and UCoGe, the fascinating aspects of the interplay between the triplet state of Cooper pairing and ferromagnetism have emerged. Furthermore, as the ferromagneticproperties in the normal state are quite different with respect to the proximity of the ferromagnetic-paramagnetic instabilities, the feedback with the coexistence of superconductivity gives rise to quite different boundaries in pressure and magnetic field. Specialattention is given on the location of the materials with respect to the tricriticality and on the reinforcement of SC in a transverse field response with respect to the direction of the FM sublattice magnetization.

実験炉組合せ照射(JRR-3⇔常陽)及びホット施設(WASTEF,JMTRホットラボ,MMF,FMF)の作業計画と作業報告; 長寿命プラント照射損傷管理技術に関する研究開発

松井 義典; 高橋 広幸; 山本 雅也; 仲田 祐仁; 吉武 庸光; 阿部 和幸; 吉川 勝則; 岩松 重美; 石川 和義; 菊地 泰二; et al.

JAEA-Technology 2009-072, 144 Pages, 2010/03

JAEA-Technology-2009-072.pdf:45.01MB

日本原子力研究開発機構は、平成17年10月に日本原子力研究所と核燃料サイクル開発機構との統合によって誕生した。この統合を最大限に利用したプロジェクトが、旧電源開発促進対策特別会計法及び特別会計に関する法律(エネルギー対策特別会計)に基づく文部科学省からの受託事業「長寿命プラント照射損傷管理技術に関する研究開発」である。この「長寿命プラント照射損傷管理技術に関する研究開発」において、材料の照射損傷評価指標の確立に重要な、世界で類のない、高速実験炉「常陽」と研究用原子炉であるJRR-3を利用した組合せ照射材を平成18年から平成19年の約2年間の短期間で取得した。本報告は、これら常陽,JRR-3の実験炉施設及びWASTEF, JMTRホットラボ,MMF, FMFのホット施設を利用した組合せ照射における作業計画から作業結果及び照射試験における照射温度と照射量の評価をまとめたものである。

JT-60UにおけるD-D反応生成プロトンに起因するICEの研究

佐藤 翔一*; 市村 真*; 山口 裕資*; 片野 誠*; 今井 康隆*; 村上 達也*; 三宅 勇一郎*; 横山 拓郎*; 森山 伸一; 小林 貴之; et al.

no journal, , 

JT-60Uで観測されるイオンサイクロトロン放射(ICE)のなかで、入射したDビームに起因するICE(D)と核反応生成(FP)イオンに起因するICEでは、トロイダル方向の波数が異なり、FPイオンによるICEは有限な波数を持つことがこれまでに観測されている。この性質を利用して、ICE(D)の2倍高調波と分離してICE(H)を同定した。ICE(H)が観測される条件を明らかにすることを目的として、実験条件の特定とEPOCコードを用いて軌道の計算をしている。

負ミュオン入射後に放出されるミュオン特性エックス線測定による元素分析

二宮 和彦; 長友 傑*; 久保 謙哉*; 喜多 真琴*; 篠原 厚*; 伊藤 孝; Strasser, P.*; 河村 成肇*; 下村 浩一郎*; 三宅 康博*; et al.

no journal, , 

電子と同じ電荷を持ち、質量が200倍の粒子である負ミュオンは、原子の電子と置き換わり、ミュオン原子を形成する。ミュオン原子からはミュオンの脱励起に伴いミュオン特性エックス線が放出される。ミュオン特性エックス線のエネルギーは、ミュオンが大きな質量を持つことから、透過力が強く物質の深部からも吸収されずに放出される。このため、ミュオン特性エックス線の測定によって非破壊の物質内部の分析ができると期待される。本研究ではJ-PARCミュオン施設より得た負ミュオンを利用しミュオン特性エックス線の測定による中国秦代の貨幣の元素分析を行った。