Evolution of magnetic domain structure of martensite in Ni–Mn–Ga films under the interplay of the temperature and magnetic field  

作　　者：谢忍 韦俊 刘仲武 唐妍梅 唐涛 唐少龙 都有为 

机构地区：[1]National Laboratory of Microstructures, Jiangsu Provincial Laboratory for Nanotechnology and Department of Physics,Nanjing University [2]School of Materials Science and Engineering, South China University of Technology

出　　处：《Chinese Physics B》2014年第6期574-579,共6页中国物理B（英文版）

基　　金：supported by the National Key Project of Fundamental Research of China(Grant No.2012CB932304);the National Natural Science Foundation of China(Grant No.50831006);the Program for New Century Excellent Talents in University(Grant No.NCET-11-0156);the Priority Academic Program Development of Jiangsu Higher Education Institutions

摘　　要：Ferromagnetic shape memory Ni-Mn-Ga films with 7M modulated structure were prepared on MgO （001） substrates by magnetron sputtering. Magnetization process with a typical two-hysteresis loop indicates the occurrence of the reversible magnetic field-induced reorientation. Magnetic domain structure and twin structure of the film were controlled by the in- terplay of the magnetic and temperature field. With cooling under an out-of-plane magnetic field, the evolution of magnetic domain structure reveals that martensitic transformation could be divided into two periods： nucleation and growth. With an in-plane magnetic field applied to a thermomagnetic-treated film, the evolution of magnetic domain structure gives evidence of a reorientation of twin variants of martensite. A microstructural model is described to define the twin structure and to produce the magnetic domain structure at the beginning of martensitic transformation; based on this model, the relationship between the twin structure and the magnetic domain structure for the treated film under an in-plane field is also described.Ferromagnetic shape memory Ni-Mn-Ga films with 7M modulated structure were prepared on MgO （001） substrates by magnetron sputtering. Magnetization process with a typical two-hysteresis loop indicates the occurrence of the reversible magnetic field-induced reorientation. Magnetic domain structure and twin structure of the film were controlled by the in- terplay of the magnetic and temperature field. With cooling under an out-of-plane magnetic field, the evolution of magnetic domain structure reveals that martensitic transformation could be divided into two periods： nucleation and growth. With an in-plane magnetic field applied to a thermomagnetic-treated film, the evolution of magnetic domain structure gives evidence of a reorientation of twin variants of martensite. A microstructural model is described to define the twin structure and to produce the magnetic domain structure at the beginning of martensitic transformation; based on this model, the relationship between the twin structure and the magnetic domain structure for the treated film under an in-plane field is also described.

关 键 词：Ni-Mn-Ga film martensitic transformation magnetically induced reorientation magnetic domain structure 

分 类 号：O484.4[理学—固体物理]