Microscopic physical properties and visualization of the crystallographic, electric, and magnetic domains in multiferroics

在温度、磁场和电场变化的条件下，利用原位透射电镜研究了多铁质材料及其相关材料的晶体学、电畴和磁畴结构。我们发现了一种与螺旋磁结构有关的调制结构，它在室温下表现出磁电性质。我们开发了一种新的观察畴结构的方法。采用原位观察的方法，我们发现了温度和磁场诱导的双钙钛矿钴酸盐结构相变。

Crystallographic, electric, and magnetic domain structures in multiferroics and the related materials were investigated by in situ TEM with changing temperature, magnetic field, and electric one. We found a modulated structure, which is related to the helical magnetic structure, in a hexaferrite which exhibits magnetoelectric properties at room temperature. We developed a new method of observation of the domain structures. By adopting the in situ observation methods, we found temperature- and magnetic-field-induced structural phase transitions in a double perovskite cobaltate.