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

D0₂₂-structure and L1₀-structure had been realized in Mn_100-xGa_x (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.