Effect of temperature on magnetic field–induced response of Ni-Mn-Ga single crystals

Abstract

This study presents an experimental and theoretical investigation into the effect of temperature on the magnetic field–induced responses of Ni-Mn-Ga single crystals, such as reorientation behaviour, critical threshold fields and hysteresis loops. Nano-indentation, differential scanning calorimetry and magnetic field–induced strain tests were conducted. The experimental results reveal that the critical threshold field decreases with an increase in temperature under a constant compressive stress. A revised magnetization rotation angle equation was developed by considering the effect of temperature on material magnetic anisotropy. By comparing with the measured magnetic field–induced strain versus magnetic field curves, the present theoretical model is shown to be capable of predicting the effect of temperature on the macroscopic responses of magnetic shape memory alloy.