High-pressure high-temperature synthesis of magnetic perovskite BiCu0.4Mn0.6O3

Complex perovskite oxides stabilized under high-pressure conditions constitute a rich playground for material science thanks to their multifunctional properties. Here we present the synthesis of BiCu0.4Mn0.6O3, obtained under isotropic high-pressure/high-temperature conditions. The compound crystallizes in the orthorhombic Pbam space group with a = 5.57960(16) Å, b = 11.2374(3) Å, c = 7.6603(2) Å. Disorder between Cu and Mn cations at the B site causes a significant interplay between electric and magnetic properties. Although a long-range magnetic order is not observed in neutron diffraction, BiCu0.4Mn0.6O3 displays a ferromagnetic-like transition at 330 K confined at the local scale and thermal-activated semiconductive behavior. At lower temperatures, the partial electronic localization on the Mn site changes the transport mechanism leading to 3D variable range hopping conductivity and determines the formation of an antiferromagnetic ordering at about 30 K. The presence of ferromagnetic-like room temperature state makes this material intriguing as a starting point for advanced multifunctional devices. High-pressure high-temperature synthesis of perovskites can stabilize highly distorted and metastable compounds to ambient conditions, allow tuning of various physical properties. Here, BiCu0.4Mn0.6O3 is synthesized under high-pressure high temperature conditions, showing antiferromagnetic order at low temperatures and a ferromagnetic-like state at room temperature.