Phase Transition with Suppression of Magnetism in $\mathrm{BiFeO_3}$ at High Pressure

Magnetic behavior of a $\mathrm{Bi^{57}FeO_3}$ powdered sample was studied at high pressures by the method of nuclear forward scattering (NFS) of synchrotron radiation. The NFS spectra from $\mathrm{^{57}Fe}$ nuclei were recorded at room temperature under high pressures up to 61.4 GPa created in a diamond anvil cell. In the pressure interval $0<P<47\,$GPa, the magnetic hyperfine field $H^\mathrm{Fe}$ at the $\mathrm{^{57}Fe}$ nuclei increased reaching a value of $\sim52.5\,$T at 30 GPa, and then it slightly decreased to $\sim49.6\,$T at $P=47\,$GPa. As the pressure was increased further, the field $H^\mathrm{Fe}$ has 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 $H^\mathrm{Fe}$ remained zero. The field $H^\mathrm{Fe}$ has recovered to low-pressure values during decompression.