酸化希土類マンガン(III、IV)の強誘電性-反強磁性同時相転移

稀土锰(III, IV)氧化物的同时铁电-反铁磁相变

• 批准号: 04452046
• 负责人: KOHN Kay
• 金额: $ 3.9万
• 依托单位: WASEDA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452046/
• 关键词: magnetic transition; helimagnetic ordering; ferroelectric transition; structural transition in solids; magnetoelectric effect; rare earth manganese oxide; EuMn_2O_5; GdMn_2O_5; TbMn_2O_5; DyMn_2O_5; HoMn_2O_5; ErMn_2O_5; TmMn_2O_5; YbMn_2O_5

We performed dielectric, magnetic, and magnetoelectric studies of a series of manganites with a formula of RMn_2O_5, where R is a rare earth between Eu and Yb, Y or Bi. In addition to the development of helimagnetic ordering of Mn spins and that of rare earth spins at lower temperature, we obtained the evidences of successive structural transitions, where these crystals tuned into ferroelectric. The origin of the spontaneous polarization was considered to be the displacements of three different kind of metallic ions Mn^3+'s, Mn^<4+>'s and R^<3+>'s. The lower magnetic transition, where the spins of R^<3+> order is generally accompanied with a structural transition with a large change in spontaneous transition.

我们对一系列分子式为RMn_2O_5的锰氧化物进行了介电、磁性和磁电性能的研究，其中R为Eu和Yb、Y或Bi之间的稀土元素。除了Mn自旋和稀土自旋在较低温度下的螺旋磁有序的发展外，我们还获得了连续结构转变的证据，这些晶体调谐成铁电体。认为自发极化的起因是三种不同的金属离子Mn^3+、Mn^4+和R^3+的位移。低磁跃迁（R^<3+>级自旋）通常伴随着自发跃迁变化较大的结构跃迁。

项目成果

Akinobu IKEDA and Kay KOHN: "Magnetoelectric Effect and Low-Temperature Phase Transiteions of YMn_2O_5" Ferroelectrics. (in press.).

Akinobu IKEDA 和 Kay KOHN：“YMn_2O_5 铁电体的磁电效应和低温相变”。

H.Tsujino: "Polar-Nonpolar Phase Transition in Rare-Earth Manganese Oxides REMn_2O_5" Proceedings of the Sixth International Conferences on Fevvites. 714-717 (1992)

H.Tsujino：“稀土锰氧化物 REMn_2O_5 中的极性-非极性相变”第六届 Fevvites 国际会议论文集。

K.Saito: "Magnetoelectric Effect and Low・Temperature Phase Transitions in TbMn_2O_5" Journal of Physics:Condensed Matler. 7. (1995)

K.Saito：“TbMn_2O_5 中的磁电效应和低温相变”物理学杂志：凝聚态材料7。（1995）

Toshiyuki DOI and Kay KOHN: "Magnetoelectric Effect and Simultaneously Electric and Magnetic Transition in EuMn_2O_5" Phase Transitions. 38-2. 273-284 (1992)

Toshiyuki DOI 和 Kay KOHN：“EuMn_2O_5 中的磁电效应和同时电磁转变”相变。

Y.Tanaka: "Magnetoelectric Effect and Low-Temperature Phase Transitians of DxMn_2O_5 Single Crystals" Ferroelectrics. (印刷中). (1994)

Y. Tanaka：“DxMn_2O_5 单晶的磁电效应和低温相变”（正在出版）。