Phase transition with suppression of magnetism in BiFeO3 at high pressure

The magnetic behavior of a Bi⁵⁷FeO₃ powdered sample was studied at high pressures by the method of nuclear forward scattering (NFS) of synchrotron radiation. The NFS spectra from ⁵⁷Fe nuclei were recorded at room temperature under high pressures up to 61.4 GPa, which were created in a diamond anvil cell. In the pressure interval 0 < P < 47 GPa, the magnetic hyperfine field H^Fe at the ⁵⁷Fe nuclei increased reaching a value of ～52.5 T at 30 GPa, and then it slightly decreased to ～49.6 T at P = 47 GPa. As the pressure was increased further, the field H^Fe abruptly dropped to zero testifying a transition from the antiferromagnetic to a nonmagnetic state (magnetic collapse). In the pressure interval 47 < P < 61.4 GPa, the value of H^Fe remained zero. The field H^Fe recovered to the low-pressure values during decompression.