Mn_(1-x)Bi_(x)CoGe合金的马氏体相变和磁热效应研究  

Martensitic transformation and magnetocaloric effect of Mn_(1-x)Bi_(x)CoGe alloys

作　　者：秦宁波 张国杰 张元磊 黄银生[1] 曾辉 李哲 刘永生[3] 敬超 QIN NingBo;ZHANG GuoJie;ZHANG YuanLei;HUANG YinSheng;ZENG Hui;LI Zhe;LIU YongSheng;JING Chao(Department of Physics,College of Science,Shanghai University,Shanghai 200444,China;College of Physics and Electronic Engineering,Qujing Normal University,Qujing 655011,China;College of Mathematics and Physics,Shanghai University of Electric Power,Shanghai 200090,China)

机构地区：[1]上海大学理学院物理系,上海200444 [2]曲靖师范学院物理与电子工程学院,曲靖655011 [3]上海电力大学数理学院,上海200090

出　　处：《中国科学：物理学、力学、天文学》2021年第6期100-106,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:51371111,51971128,51661029)资助项目。

摘　　要：MnCoGe添加部分元素形成的四元合金能使其结构转变和磁转变发生耦合,在马氏体相变过程表现出明显的磁热效应,进一步得到更大的磁熵变.我们利用氩气保护下的电弧熔炼方法制备了Mn_(1-x)Bi_(x)CoGe (x=0, 0.03,0.04, 0.05, 0.055, 0.06)系列合金样品.实验结果表明,随着Bi元素掺杂量的增加,样品的结构转变温度(TM)向低温方向移动. Mn0.945Bi0.055CoGe合金(价电子浓度e/a=6.63)在室温附近发生一级磁-结构转变,在外磁场改变量为5 T时,获得的磁熵变大小为36.8 J kg^(-1)K^(-1),说明Bi元素的掺杂能有效调控MnCoGe合金的马氏体相变温度和进一步提高磁熵变.Quaternary alloys of Mn Co Ge with the partial addition of other elements can realize coupling between structural and magnetic transformations, and it can present apparent magnetocaloric effects during martensitic transformation. In this paper, we have prepared Mn_(1-x)Bi_(x)CoGe(x=0, 0.03, 0.04, 0.05, 0.055, 0.06) series alloys using arc melting in a protective argon atmosphere. Experimental results indicate that the structural transformation temperature(TM) of the samples shifts to low temperatures with increasing elemental Bi doping. The Mn0.945 Bi0.055 Co Ge alloy(valence electron concentration e/a=6.63) undergoes a first-order magnetostructural transition(FOMST) near room temperature, and a large magnetic entropy change of 36.8 J kg^(-1) K^(-1) is obtained under an external magnetic field of 0–5 T, which proves that elemental Bi doping in Mn Co Ge alloys can effectively tune the martensitic transformation temperature and further improve the magnetic entropy change.

关 键 词：一级磁-结构转变 马氏体相变 价电子浓度 磁热效应 

分 类 号：TB64[一般工业技术—制冷工程] TG132.27[一般工业技术—材料科学与工程]