Magnetization and magnetostriction of Terfenol-D near spin reorientation boundary

Magnetization and magnetostriction behaviors of quasi-binary Tb_xDy_1−xFe₂ alloys (Terfenol-D) near spin reorientation boundary (SRB) between 〈111〉 and 〈100〉 easy axes are studied by computer simulation of magnetic domain rotations under increasing magnetic field and compressive stress along $[112]$ growth direction. The simulation results reveal coexistence of 〈111〉 and 〈100〉 domains near SRB and show that the switching field first decreases then increases when crossing the SRB from the 〈100〉 region into the 〈111〉 region of the quasi-binary phase diagram, while the magnetostriction first increases then saturates, thus providing an optimal combination of large magnetostriction and low switching field near the SRB as desired for actuator application. This finding has general implications for other magnetostrictive quasi-binary alloys that also exhibit spin reorientation phenomenon, allowing material design for improved magnetostrictive property near SRB, in analogy to morphotropic phase boundary ferroelectrics.