采用固相反应法制备了钙钛矿锰氧化物La0 3Ca0 7Mn1-xWxO3(x=0.08,0.12)样品,通过M-T曲线、M-H曲线、ESR曲线研究了在Mn位掺W对La0 3Ca0 7MnO3电荷有序相的影响以及磁结构的变化过程.结果表明:当x=0.08时,体系存在电荷有序(CO)相,相变温度TcO=275 K,在T>275 K时体系表现为PM;当温度从275 K下降到230 K,体系在CO相下从自旋无序的顺磁态向自旋有序的反铁磁态转变;在230 K至5 K形成长程反铁磁态,AFM/CO态共存;低温区在AFM/CO态本底中存在一定的铁磁成分.当x=0.12时,体系的CO相已基本融化,150 K以下还残留少量CO相.在高于150K温区表现为顺磁;在低于150K温区从顺磁向铁磁转变.
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