Charge Disproportionation and Complex Magnetism in a PbMnO₃Perovskite Synthesized under High Pressure

Because of the possible crossover of Pb and 3d transition-metal (TM) redox levels, a charge transfer between Pb and TM leads to a continuous evolution from Pb2+Ti4+O3 to Pb4+Ni2+O3 in the perovskite family of PbTMO3 as verified by several reports. However, very little information is known about PbMnO3 in the PbTMO3 series. The perovskite PbMnO3 is the most difficult one to synthesize, although its geometric tolerance factor is close to 1. Here, we report a careful study of PbMnO3 synthesized under 15 GPa by a structural refinement and high-precision X-ray absorption spectroscopy (XAS) as well as a variety of measurements of physical properties. We can rationalize the physical properties of PbMnO3 based on a local bonding model and the valence states of Pb and Mn from XAS. Moreover, the complete study of PbMnO3 allows us to construct a more consistent picture of the valence evolution and the charge disproportionation for the entire family of PbTMO3 perovskites.