Phase-field simulation of domain structures and magnetostrictive response in Tb_1-xDy_xFe₂ alloys near morphotropic phase boundary

Phase-field method micromagnetic microelastic modeling is employed to simulate the thermal domain stability and enhanced magnetostrictive responses around the ferromagnetic morphotropic phase boundary (MPB) in giant magnetostrictive Tb_1-xDy_xFe₂ (x≈0.27) single crystal. The simulation shows that the rhombohedral and tetragonal phases coexist in equilibrium in the vicinity of MPB region due to the balance of weak magnetocrystalline anisotropy and strong exchange, magnetostatic and ferroelastic interaction. Enhanced magnetostrictive response is found in the vicinity of MPB, which could be attributed to the low-energy rotating pathways of local magnetization vectors in the phase coexisting region.