Ni_(50-x)Mn_(10+x)Ga_(30)Cu_(10)系列Heusler合金的结构、马氏体相变和磁性研究  

Structure,martensitic transformation and magnetism of Ni_(50-x)Mn_(10+x)Ga_(30)Cu_(10) Heusler alloys

作　　者：李贵江[1] 刘恩克[1] 王文洪[1] 陈京兰[1] 吴光恒[1] 

机构地区：[1]中国科学院物理研究所磁学国家重点实验室,北京100190

出　　处：《中国科学：物理学、力学、天文学》2012年第7期677-683,共7页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金资助项目(批准号:51031004)

摘　　要：通过实验和第一性原理研究了Ni50-xMn10+xGa30Cu10(x=0-10)系列Heusler合金的结构、马氏体相变和磁性.实验研究发现,当用Mn原子在化学上替换Ni原子,合金的晶格参数随成分线性增大,相应体系的马氏体相变温度线性降低;理论分析认为,体系合金的单胞尺寸和电子浓度的共同作用使马氏体相变温度随成分变化线性降低直至消失;体系中Mn对Ni原子的替换使交互作用较强的Ni(A,C)-Mn(B)原子对逐渐形成,这增强了磁性原子间总的交换耦合作用,实验观测到体系合金的居里温度随成分逐渐上升.基于KKR-CPA-LDA的第一性原理计算结果表明,在体系合金中Mn原子磁矩始终与Ni原子磁矩保持铁磁排列,且Mn原子为体系分子磁矩的主要贡献者,因此体系合金的分子磁矩随Mn原子数量线性增加,这与实验结果相一致.The structure, martensitic transformation temperature investigated by experiment and KKR-CPA-LDA method and magnetism of Ni50-xMn10＋xGa30CU10 alloys were in this paper. It was experimentally found that, with the substitution of Mn for Ni atoms, the structure of the alloys changes from the coexistence of martensite and austensite structure to the single autensite structure, and the corresponding lattice parameter increases linearly. It was theoretically analyzed that martensitic transformation temperature decreases with the increase of cell volume and the decrease of electron concentration, which change the electronic structure of the alloys. The overall exchange interaction becomes stronger with the increase of Ni-Mn atomic pairs （in the nearest neighbour）, resulting in the enhancement of the experimentally observed Curie temperature. From the calculations by KKR-CPA-LDA method, the Mn atoms are the main magnetic contributor of the magnetism and their magnetic moments always parallelly align to those of Ni atoms. Thus, the molecular magnetic moments linearly increase with the increase of Mn atoms number, which is well consistent with the experimental results.

关 键 词：马氏体相变 HEUSLER合金 结构与磁性 第一性原理计算 

分 类 号：TG146.15[一般工业技术—材料科学与工程]