Role of the electronic structure in the morphotropic phase boundary of Tb_xDy_1−xCo₂studied by first-principle calculation

Physically parallel to ferroelectric morphotropic phase boundary, a phase boundary separating two ferromagnetic phases of different crystallographic symmetries was experimentally found in Tb_xDy_1−xCo₂via high-resolution synchrotron X-ray diffraction. However, lack of the theoretical support makes the morphotropic phase boundary in ferromagnetic system debatable. Here, a first-principle calculation was employed to investigate the electronic structure variation during the morphotropic phase transition in Tb_xDy_1−xCo₂. It offers a theoretical basis for the ferromagnetic phase of different crystallographic symmetries in Tb_xDy_1−xCo₂. It also provides an explanation for why morphotropic phase boundary occurs in Tb_xDy_1−xCo₂alloys and offers a serviceable method to search for the morphotropic phase boundary phenomena in other alloys via computational rather than experimental method.