High-pressure synthesis of half-doped perovskites MnV_0.5Nb_0.5O₃ and MnV_0.5Ta_0.5O₃ with unusual A-site small Mn²⁺ cations

We have successfully synthesized two new half-doped perovskites, MnV0.5Nb0.5O3 and MnV0.5Ta0.5O3, with unique small Mn2+ cations at the A site under high-temperature and high-pressure conditions (6 GPa and 900-1300 degrees C). Synchrotron X-ray structure analysis confirmed their crystal structures to belong to the space group Pnma, and they do not exhibit features of an ordered perovskite (double perovskite) structure. Magnetic property measurements revealed an essentially antiferromagnetic nature below 17 and 18 K for both compounds, respectively, accompanied by a small contribution of thermal and magnetic field hysteresis. Electrical conductivity measurements showed activation energies of 0.13 and 0.31 eV, respectively, suggesting semiconductor-like behavior. These findings underscore the potential of these materials with unusual A-site small Mn2+ cations for electronic and magnetic devices, warranting further studies to explore their unique magnetic and electronic properties.