Effects of doping on structural, physical, and chemical properties of multiferroic BiMnO₃ and BiCrO₃

Abstract

Effects of isovalent substitutions in the Mn(Cr)- and Bi-sublattices of BiMnO₃ and BiCrO₃ on the magnetic, structural, and chemical properties have been studied. Phase diagrams in the whole compositional range were constructed for BiMn_1-xSc_xO₃, BiMn_1-xCr_xO₃, and Bi_1-xR_xMO₃ (R = Y and La, M = Cr and Mn). BiMn_1-xSc_xO₃ and BiMn_1-xCr_xO₃ keep the monoclinic C2/c structure at RT for all x values; a spin-glass transition was found for x ≥ 0.4 in BiMn_1-xSc_xO₃ and at x = 0.4 and 0.5 in BiMn_1-xCr_xO₃. Magnetic phase diagrams of BiMn_1-xSc_xO₃ and BiMn_1-xCr_xO₃ are similar to each other for x ≤ 0.5. In Bi_1-xR_xMO₃, the Pnma modification is stabilized very fast with x; the Pnma phases show antiferromagnetic transitions with weak ferromagnetism.