Mn_(1.3)Fe_(0.7-x)V_xP_(0.45)Si_(0.55)系列化合物的磁热效应  

Magnetocaloric Effect in Mn_(1.3)Fe_(0.7-x)V_xP_(0.45)Si_(0.55) Compounds

作　　者：刘雨江[1] 耿遥祥[1] 特古斯[1] 哈斯朝鲁[1] 宋志强[1] 海山[1] 利胜 

机构地区：[1]内蒙古师范大学内蒙古自治区功能材料物理与化学重点实验室,内蒙古呼和浩特010022

出　　处：《内蒙古师范大学学报（自然科学汉文版）》2012年第4期368-371,共4页Journal of Inner Mongolia Normal University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(50661044;50961010);内蒙古自然科学基金资助项目(20080404Zd0;20080404D09)

摘　　要：报道了用V替代Fe后,一级相变材料Mn1.3Fe0.7-xVxP0.45Si0.55(x=0,0.05,0.1,0.15)的结构、磁性和磁热效应.XRD的结果表明,该系列化合物均形成Fe2P型六角结构,空间群为P-62m;随着V含量的增加,该系列化合物的晶格常数和晶胞体积有明显的变化规律.磁性测量结果表明,随着温度的升高,化合物经历由铁磁到顺磁的一级相变过程,热滞无明显规律,在2.4K到3.2K之间波动,当V的含量为0.05时,化合物的热滞最小,为2.4K.随着V含量的增加,化合物的居里温度明显降低,但磁熵变的半峰宽随V含量的增加逐渐增大.在1.5T外磁场下,该系列化合物的最大磁熵变由x=0时的7.7J/(kg.K)迅速降低到x=0.15时的1.45J/(kg.K).这说明V替代Fe后,不利于磁热效应的增加,但是V的加入可以调节化合物的居里温度和热滞的大小,并且能够增加熵变的半峰宽值.In this paper we report on the structural,magnetic and magnetocaloric properties of the first-order phase transition materialMn1.3Fe0.7-xVxP0.45Si0.55（x=0,0.05,0.1,0.15）.The XRD results show that the compounds crystallize in the Fe2P-type hexagonal structure with space group of P-62m.The lattice constants and unit cell volume are changed obviously with increasing the content of V.All the compounds experience a ferromagnetic-paramagnetic first-order phase transition.The thermal hysteresis of the compounds fluctuates between 2.4 K to 3.2 K and a minimal thermal hysteresis about 2.4 K is found in Mn1.3Fe0.65V0.05P0.45Si0.55 compound.The Curie temperature gradually decreases with increasing the V content,but the half peak value of magnetic entropy change gradually increases by adding V.The magnetic-entropy change of Mn1.3Fe0.7P0.45Si0.55compound is about 7.7J/（kg·K） in a exteral magnetic field of 1.5T,but it sharply decreases to 1.5J/（kg·K） when the content of V is 0.15.This means that the V atoms replace the iron atoms,is not conducive to the increase of magnetocaloric effect,but can be used to adjust Curie temperature,thermal hysteresis and to increase half peak value,which are technically important for applications.

关 键 词：一级相变 磁热效应 居里温度 热滞 磁熵变 

分 类 号：O482.54[一般工业技术—材料科学与工程]