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

The magnetocrystalline anisotropy and magnetoelasticity of preferentially oriented martensitic variants in an off-stoichiometric Ni₅₂Mn₂₄Ga₂₄ single crystal were 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 Ni₅₂Mn₂₄Ga₂₄ have been determined. It was found that at martensite phase, the anisotropy field increases monotonically with decreasing temperature, but the anisotropy constant first increases rapidly and then the increasing rate become smaller and smaller. Based on a previous model, 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.