Magnetic field-induced stress in the Ni–Mn–Ga magnetic shape memory alloy

Magnetic Shape Memory (MSM) materials generate stress in a magnetic field, which can change the shape of the material. Up to now, little work has been carried out in modeling and measuring the magnetic field-induced (MFI) stress in MSM materials. In the present study, direct MFI stress measurements in a Ni–Mn–Ga MSM material, giving full 6% MFI strain, were performed at different field strengths. The MFI stress was also calculated from the magnetic anisotropy of the material, based on the magnetization curves along the easy and the hard magnetization directions. Both measurement methods are described in detail. The measurement results demonstrated good agreement with the calculated ones. The dependence of the MFI stress on the MFI strain and the magnetic field strength was also revealed. Potential errors during MFI stress measurements in MSM materials are discussed, and avoided by properly selecting the measurement conditions during the study.