Synthesis of novel magnetic ferroelectrics under high pressure with the use of ion exchange and hydrothermal reactions

利用环境压力相的单晶前驱体，采用高压技术成功地获得了高质量的钙钛矿Eu_<1-x>Y_xMnO_3和Y_<1-x>Y_xMnO_3多晶样品。建立了正交RMnO_3的完整多铁相图。此外，我们发现在双临界相边界附近磁电响应增强。在准水热条件下，在高压下成功地生长了钙钛矿YMnO_3单晶。利用同步x射线，我们首次观察到YMnO_3中由磁序驱动的铁电晶格位移。

We have succeeded in obtaining high-quality polycrystalline samples of perovskite Eu_<1-x>Y_xMnO_3 and Y_<1-x>Y_xMnO_3 by a high pressure technique with using single crystalline precursors of the ambient pressure phase. Complete multiferroic phase diagram of orthorhombic RMnO_3 was established. Furthermore, we have found that the magnetoelectric response is enhanced near the bicritical phase boundary. Single crystals of perovskite YMnO_3 were successfully grown under high pressure with a quasi hydrothermal condition. By using a synchrotron x-ray, we have observed for the first time ferroelectric lattice displacement driven by a magnetic order in YMnO_3.