颗粒系统稀土掺杂氧化物的磁电阻效应

具有钙钵矿结构的稀土掺杂氧化物具有很强的磁电阻效应，该类材料所显示的复杂的物理现象和可能的应用前景引起人们的很大兴趣。但是其磁转变温度一般低于室温，而且需要很高的外加磁场才能够饱和。为实现室温和低场磁电阻，人们采用多种方法，如制备复合材料或尺寸在纳米量级的多晶体系。本文重点介绍了锰酸盐颗粒体系的结构特点、磁电阻效应以及产生成电阻效应的可能机理。

Magnetoresistance effects in granular rare-earth doped oxides

There is quite large magnetoresistance in perovskite - type rare - earth doped oxides which induce much interest with people for the complex physical mechanism and the potential in device applications. Therefore, the magnetic transition temperature of this kind of materials is usually lower than the room temperature and only high magnetic field can saturate them. In order to realize the magnetoresistance effects in room temperature or low magnetic field, many ways have been taken, such as preparing combined materials or nanosized polycrystalline samples. The structure and magnetoresistance effects as well as the probable mechanism of the magnetoresistance effects in the manganites system are introduced emphatically in this paper.