V掺杂对La_(0.45)Ca_(0.55)MnO_3电荷有序态及输运性质影响的研究  

Influence of Doping V on Transport Properties and Charge Ordering of La_(0.45)Ca_(0.55)MnO_3

作　　者：王桂英[1] 严国清[1] 彭振生[1,2] 刘宁[1,2] 

机构地区：[1]自旋电子与纳米材料安徽省重点实验室培育基地宿州学院电子与电气工程系,安徽宿州234000 [2]中国科技大学合肥微尺度物质科学国家实验室,安徽合肥230026

出　　处：《稀有金属》2010年第3期345-351,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金重点项目(19934003);国家重大研究计划课题(2007CB925001);安徽省教育厅自然科学研究项目(KJ2009B281Z);安徽省教育厅自然科学研究重大项目(ZD2007003-1);安徽省教育厅自然科学研究重点项目(KJ2008A26ZC)和安徽省教育厅自然科学研究重点项目(KJ2008A19ZC)资助

摘　　要：采用标准固相反应法制备了La0.45Ca0.55Mn1-xVxO3(x=0.00,0.06,0.10,0.12)多晶样品。通过XRD、ρ-T曲线、M-T曲线和ρ-T拟合曲线,研究了Mn位V5+离子掺杂对体系的电荷有序相及输运性质的影响。实验结果表明:随着V5+离子的掺杂量的增加,电荷有序相(CO)逐渐削弱,当x=0.10时,CO相基本融化但还有部分残留,当x=0.12时CO相完全融化;对低掺杂(x=0.00,0.06)样品,表现出复杂磁相:随温度降低,发生顺磁-电荷有序-反铁磁相变,40 K附近,在反铁磁背景下产生再入型自旋玻璃态;随掺杂量增加,体系的电阻率逐渐减小,当掺杂量x≥0.10时,样品发生金属-绝缘体相变,其相变温度随着掺杂量的增加而向高温移动。对于金属型导电机制满足自旋波散射和电-磁子之间的散射,而绝缘体导电机制有两种情况:x≤0.10的样品满足变程跃迁模型ρ=ρ0exp(T0/T)1/4,x=0.12的样品则满足小极化子绝热最近邻跃迁模型ρ=ATexp(Eα/κBT),通过掺杂实现了从变程跃迁到绝热小极化子最近邻跃迁。The polycrystalline samples of La0.45Ca0.55Mn1-xVxO3(x=0.00,0.06,0.10,0.12) were prepared by the standard solid-state reaction.Influence of V doping at Mn-site on transport properties and charge-ordering phase was researched through the measurements of XRD,ρ-T curve and M-T curve.The results showed that charge ordering became weaker gradually with the increase of V doping level and melted completely when x=0.12;samples of low V doping(x=0.00,0.06) exhibited complex magnetic phases,the paramagnetism-charge o...

关 键 词：钙钛矿锰氧化物 电荷有序 V掺杂 再入型自旋玻璃态 

分 类 号：O482.5[理学—固体物理]