球磨Gd的输运性质和双磁热效应研究  

Transport Property and Double Magnetocaloric Effect Peaks in Milled Gd

作　　者：章冉 曾春阳 王芳[1,2] 冯唐福[1] 孙仁兵[1] 胡国琦[1] 王亚娟[1] ZHANG Ran;ZENG Chunyang;WANG Fang;FENG Tangfu;SUN Renbing;HU Guoqi;WANG Yajuan(School of Materials and Chemical Engineering,Ningbo University of Technology,Ningbo 315211,China;Zhejiang Institute of Tianjin University,Ningbo 315211,China)

机构地区：[1]宁波工程学院材料与化学工程学院,浙江宁波315211 [2]天津大学浙江研究院,浙江宁波315211

出　　处：《宁波工程学院学报》2023年第2期1-5,共5页Journal of Ningbo University of Technology

基　　金：天津大学浙江研究院—宁波工程学院专项(ZITJU2022-ZYHY012);宁波工程学院大学生科技创新项目(202205);宁波工程学院教师个人科技发展基金(0080011541060,0080011541011)。

摘　　要：为了研究无序对稀土Gd磁性能的影响,采用机械球磨技术将无序态引入到稀土金属Gd中,并系统研究了其结构、输运性质及磁热效应。无序导致磁化强度急剧降低,室温附近的等温磁熵变为6.4 J·kg^(-1)·K^(-1),低于块体Gd(9.7 J·kg^(-1)·K^(-1))。但同时在33 K出现另一等温磁熵变峰值,该磁熵变与球磨后Gd在低温下出现的团簇冻结有密切关系;在稀土金属中首次观察到欧姆行为的负巨磁电阻效应,该效应主要起源于无序边界区域的自旋相关散射。To investigate the effect of disorder on the magnetic properties of rare earth Gd,disorder was introduced into Gd by the mechanical milling technique and its structure,transport properties,and magnetocaloric effect were systematically studied in the present paper.The disorder leads to a sharp decrease in magnetization,and the isothermal magnetic entropy change near the room temperature is 6.4 J·kg^(-1)·K^(-1),which is lower than that of the block Gd(9.7 J·kg^(-1)·K^(-1)).Another peak of isothermal magnetic entropy change was also observed at 33 K,which was related to the cluster freezing of Gd at the low temperature after ball milling.A negative giant magnetoresistance was observed for the first time in milled Gd systems.It shows an Ohmic behavior,not a tunneling type.It was mainly originated from the spin-dependent scattering at the disordered boundary region.

关 键 词：无序 巨磁阻 磁致热效应 

分 类 号：O469[理学—凝聚态物理]