La1-xZnxMnO3和La（2/3）Sr（1-x）/3Znx/3MnO3的磁电输运特性

用固相反应方法制备La1-xZnxMnO3和La2/3Sr(1-x)/3Znx/3MnO3化合物。La1-xZnxMnO3在不同掺杂浓度x的研究表明:Zn2 在一定浓度范围内掺杂,具有钙钛矿结构,但掺杂浓度在50%~70%时有ZnO衍射峰,其电阻率在100 K以上随温度而下降,当掺杂浓度为x=0.3时电阻率最低。当Zn2 和Sr2 共掺而保持La3 浓度不变,即载流子浓度不变,维持Mn3 /Mn4 =2:1,随Zn2 掺杂浓度增大,铁磁-顺磁转变温度降低,磁阻效应增大。低场磁阻效应与Zn2 掺杂浓度无关,而与温度有关;高场磁阻效应随掺杂浓度增大而增大。

Magnetotransport Properties of La_(1-x)Zn_xMnO_3 and La_(2/3)Sr_((1-x)/3)Zn_(x/3)MnO_3 Compounds

The La1-xZnxMnO3 and La2/3Sr(1-x)/3Znx/3MnO3 compounds were prepared by conventional solid-state reaction method.The study on La1-xZnxMnO3 compound shows that there exists perovskite structure in all doping contents while the diffraction peaks of ZnO appears when the doping content of Zn2 is in the range of 50% ~ 70%.The resistivity of these compounds decreases with increase of temperature.The resistivity of the compound with x=0.3 is lowest and the magnetic field have an obvious effect on the resistivity.However,the results of Zn2 and Sr2 codoping with the fixed Mn3 /Mn4 =2:1 ratio show that the peak resistivity and curie transition temperature decrease while the magnetoresistance(MR) increases by increasing Zn2 doping content.The low-field magnetoresistance(LFMR) remains unchanged while the high-field magnetoresistance increases by increasing Zn2 doping content.