Pressure-induced transition from a charge-disproportionated antiferromagnetic state to a charge-uniform ferromagnetic state in Sr(2/3)La(1/3)FeO3.

The perovskite oxide Sr(2/3)La(1/3)FeO3 has been found to switch its electronic ground state drastically at 23 GPa through measurements of 57Fe Mössbauer spectroscopy and powder x-ray diffraction up to 56 GPa. In the low-pressure region a first-order transition from a charge-uniform paramagnetic metallic phase to a charge-disproportionated (3Fe(11/3+)-->2Fe(3+)+Fe5+) antiferromagnetic insulating phase occurs at 207 K at 0.1 MPa and 165 K at 21 GPa, typically. Above 25 GPa, however, a charge-uniform ferromagnetic (and most probably metallic) phase persists below 300 K. This switching occurs at a lattice volume of V(23 GPa)/V(0)(0.1 MPa) = 0.89.