Distinct magnetic responses under hydrostatic pressure in Mn-Ga phase with variant crystallographic structure

D022-structure and L10-structure had been realized in Mn100-xGax (x = 67.5, 70, 72.5 and 75) annealed ribbons and identified by X-ray diffraction and transmission electron diffraction. The Mn-dependent Curie temperature and coercivity had been studied. By applying hydrostatic pressure of 2.5 kbar, the coercivity had been enhanced in D022-structured ribbons but a kink was observed on the hysteresis loop of L10-structured ribbon. The different effects of hydrostatic pressure on magnetic coupling were also observed in the ribbons possessing D022-and L10-structure. They were explained by the affected magnetocrystalline anisotropy in D022-and L10-structures under hydrostatic pressure, which was further verified by the first-principles calculations. Our work demonstrated the feasibility of tuning coercivity of hard magnetic materials by hydrostatic pressure besides of the conventional microstructural optimization.