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

点击翻译按钮获取中文摘要

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.