La_(0．3)Ca_(0．7)Mn_(1-x)W_xO_3体系中电荷有序及磁性质研究  

Research on Charge Ordering and Magnetic Properties in La_(0.3)Ca_(0.7)Mn_(1-x)WxO_3 System

作　　者：彭振生[1] 郭焕银[1] 严国清[1] 毛强[1] 

机构地区：[1]宿州学院材料研究室

出　　处：《稀有金属材料与工程》2006年第A02期202-205,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金重点项目(19934003);国家重点基础研究发展规划项目(001CB610604);安徽省教育厅自然科学研究计划项目(2004Kj331);安徽省高等学校自然科学研究项目(2005KJ234)资助

摘　　要：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150 K温区表现为顺磁;在低于150 K温区从顺磁向铁磁转变。The perovskite manganite sample La0.3Ca0.7Mn1-xWxO3 （x=0.08, 0.12） was prepared by the solid-state reaction method. The effect of W doping at Mn site on La0.3Ca0.7MnO3 charge ordering phase and the changing process of magnetic properties were studied through the measurement of M-T curve, M-H curves and ESR curves of the sample. The results show that when x=0.08, charge ordering （CO） phase exists in the system, the transition temperature TCO=275 K, the system exhibits PM when T〉 275 K. The system transforms from spin-disordering paramagnetism to spin-ordering antiferromagnetism in charge ordering state with temperature decreasing from 275 K to 230 K. The long-range antiferromagnetism forms and AFM/CO states coexist between 230 K and 5 K. There is a little ferromagnetic component in AFM/CO background in low temperature range. When x=0.12, the CO phase in the system almost melted completely. There is a little remnant of CO phase below 150 K. The system exhibits paramagnetism when T〉150 K and transforms from paramagnetism to ferromagnetism when T〈150 K.

关 键 词：钙钛矿锰氧化物 电荷有序 融化 磁性质 

分 类 号：TB34[一般工业技术—材料科学与工程]