Study of electron-doped manganite single crystals using high-pressure synthesis methods

点击翻译按钮获取中文摘要

So far, there have been few studies on "electron-doped" manganites, the Mn valence of which is close to 4+. By using high-pressure synthesis methods, recently, we succeeded in synthesizing the single crystals of SrMnO_3, which is a parent compound with Mn^<4+> ions. In this project, by controlling the carrier number and/or lattice constant with partial substitution of Sr ions, we have revealed the overall features of electronic and lattice states for the electron-doped manganites. In particular, we have found a novel insulator-metal transition accompanied by a magnetic transition, which is controllable with 1% carrier doping. Furthermore, we have discovered a ferroelectric transition with off-center Mn^<4+> ions by substituting Sr ions with Ba ions. The ferroelectric properties are much nicer than those for the conventional multiferroic materials. These materials would be quite promising for future spintronic technology.