Magnetocrystalline Anisotropy and Magnetoelasticity of Preferentially Oriented Martensitic Variants in Ni52Mn24Ga24 Single Crystals

摘要

The magnetocrystalline anisotropy and magnetoelasticity of preferentially oriented martensitic variants in an off-stoichiometric Nis2Mn24Ga24 single crystal have been investigated. We found that the easy magnetization direction of the martensite phase is the [110] direction, and the hard magnetization exhibited in [001], the growth direction of single crystals. The temperature dependence of the anisotropy fields and constants of Ni52Mn24 Ga24 have been determined. It was found that, at the martensite phase, the anisotropy field increases monotonically with decreasing temperature, but the anisotropy constant first increases rapidly and then the increasing rate becomes smaller and smaller. Based on a previous model, the present results suggest that the competition between the Zeeman energy and the magnetocrystalline anisotropy energy is mainly responsible for the magnitude of magnetic-field-induced strain in this material.