纳米材料中的巨磁电阻效应

STRUCTURES,ELECTRIC AND MAGNETIC PROPERTIES AND COLOSSAL MAGNETOREESISTANCE OF THE RE 1-x T x MnO 3 OXIDES

纳米材料是指三维空间尺度中至少有一维处于纳米量级的材料，通常为１—１００ｎｍ，如纳米微粒，纳米线、管，纳米薄膜或其组合材料，近年来纳米材料中的巨磁电阻效应颇受人们青睐，本文将重点介绍颗粒膜，颗粒合金薄带，非连续多层膜，颗粒—薄膜混合型膜以及磁性隧道结的巨磁电阻效应。

REMnO 3 oxide (RE=La,Pr,Nd,Sm) has structure with perovskite type.If the rare earth element is partially doped with divalent alkali metal,the RE 1-x T xMnO 3(T=Ca,Sr,Ba,Pb) oxides can be formed.The crystal and electronic structures,electric and magnetic properties change largely when the component of the doped element increases.Recently,in those Mn oxides the colossal magnetoresistant effect was found,and its value is higher than 10 6%.The complex phenomena and the potantial application of those materials resulted in mush interesting for the scientists and engineers.In this paper the changes of the experimental results of the crystal and electronic structures,electric and magnetic properties,and also colossal magnetoresistance(CMR) for these Mn oxides will be introduced,and also the possible mechanism of CMR will be discussed.