Nd_(0.3)Sr_(0.7)Mn_(1-x)Cr_xO_3(0.01≤x≤0.15)的低温热导率研究  

LOW TEMPERATURE THERMAL CONDUCTIVITY OF Nd_(0.3)Sr_(0.7)Mn_(1-x)Cr_xO_3(0.01≤x≤0.15)

作　　者：高惠平[1] 吴柏枚[2] 李波[1] 魏义永[1] 

机构地区：[1]中国科学技术大学物理系,合肥230026 [2]中国科学技术大学结构开放实验室,物理系合肥230026

出　　处：《低温物理学报》2006年第3期228-231,共4页Low Temperature Physical Letters

基　　金：国家自然科学基金(项目编号:No.10174070)资助的课题~~

摘　　要：报道Nd0．3Sro．7Mn1-xCrxO3（0．01≤x≤0．15）的热导率在10-300K温区内随温度和Cr含量的变化关系,在所测温区，随着Cr掺杂的增加，样品热导率值整体上逐渐减小，但在x=0．15时，出现反弹．热导率值在绝缘体-金属转变附近有很大提高，这个提高随Cr含量的增加逐渐被压制，直到x=0．15消失．分析指出热导率在绝缘体-金属转变附近的提高是由声子热导率和自旋相关热导率两部分贡献的；Cr掺杂通过电荷、晶格和自旋相互作用影响和制约了热导率随温度的变化,结果表明体系中自旋对热导率的调制作用是不可忽略的。The temperature and Cr-doping dependence of thermal conductivity K in Nd0.3Sr0.7Mn1-xCrxO3 （0. 01 ≤x≤0.15） was measured in the temperature region of 10 -300K. With the Cr content increasing, the absolute value of K is decreased gradually in all temperature studied, but it rebounds when the Cr content is 0.15. There is a sharp increase of K near the insulating-metallic transition temperature （TIM） , but such an increase is depressed gradually by increasing Cr-doping and disappears when x reaches 0.15. We suggest that the K enhancement near TIM is contributed to both the phonon thermal conductivity and the spin-dependent thermal conductivity; Cr-doping affects and restricts the temperature dependence of K through the coupling between charge, phonon and spin. The results indicate that the modulation effect of spin on K can not be neglected freely in this system.

关 键 词：热导率 掺杂 钙钛矿锰氧化物 自旋 

分 类 号：O513[理学—低温物理]