Volume and structural study of Fe64Mn36 anti-ferromagnetic Invar alloy under high pressure

► We have investigated the pressure variation of volume and structure of FCC Fe64Mn36 alloy. ► We discovered that the change in inclination of the pressure-volume (P-V) curve of the FCC structure becomes discontinuous at a pressure of 4 GPa. This pressure corresponds to the Neel temperature, which decreases down to room temperature. ► Further we estimated bulk modulus and volume at zero pressure using the Birch-Murnaghan equation of state. As a result, we have demonstrated that anti-ferromagnetism has very close relationship with the bulk modulus and lattice volume. Moreover we discuss relationship between pressure-induced structural transition from FCC to HCP and magnetism. ► Our research is demonstrated with magneto-volume coupling of anti-ferromagnetic Fe-based alloy.