Low-Temperature Cationic Rearrangement in a Bulk Metal Oxide

Cationic rearrangement is a compelling strategy for producing desirable physical properties by atomic-scale manipulation. However, activating ionic diffusion typically requires high temperature, and in some cases also high pressure in bulk oxide materials. Herein, we present the cationic rearrangement in bulk Mn₂FeMoO₆at unparalleled low temperatures of 150–300^oC. The irreversible ionic motion at ambient pressure, as evidenced by real-time powder synchrotron X-ray and neutron diffraction, and second harmonic generation, leads to a transition from a Ni₃TeO₆–type to an ordered-ilmenite structure, and dramatic changes of the electrical and magnetic properties. This work demonstrates a remarkable cationic rearrangement, with corresponding large changes in the physical properties in a bulk oxide at unprecedented low temperatures.