Pressure Induced Amorphization of Pb²⁺ and Pb⁴⁺ in Perovskite PbFeO₃

Perovskite-type oxides have been the subject of intense research due to their various fascinating physical properties stemming from their charge degree of freedom. PbFeO3 has an unusual Pb0.52+Pb0.54+Fe3+O3 charge distribution with a long-ranged ordering of Pb2+ and Pb4+ and two inequivalent Fe3+ sites in a perovskite structure. Combined synchrotron X-ray diffraction and M & ouml;ssbauer spectroscopy revealed a change to an orthorhombic GdFeO3 structure with a unique Fe3+ site and randomly distributed Pb2+ and Pb4+ at 29.0 GPa, namely, pressure-induced amorphization of Pb2+ and Pb4+. The absence of a charge transfer transition to the Pb2+Fe4+O3 phase, which was expected from the comparison with PbCrO3 and PbCoO3, was verified using ab initio density functional theory calculations in the range of 0-70 GPa.