Effect of chemical modification on the structure and dielectric and magnetic properties of multiferroic (1 – x)BiFeO3-xDyFeO3 solid solution

Abstract

The solid solution of (1-x)BiFeO3-xDyFeO3 was prepared by solid state reactions in the form of ceramics. The effects of chemical modification by means of aliovalent ionic substitution of Ti4+ for Fe3+ on the structure and dielectric properties were investigated. A morphotropic phase boundary bridging the perovskite rhombohedral phase and the orthoferrite orthorhombic phase was identified at x around 0.1. The chemical modification was found to stabilize the perovsite phase. The dielectric performance of the solid solution was improved by the substitution of Ti4+ for Fe3+, which decreased the electric conductivity by reducing oxygen vacancies, as evidenced by the decrease in loss tangent values. Magnetic hysteresis and large saturated magnetization (0.5 μB/f.u.) were realized in 0.92BiFeO3-0.08DyFeO3 with 2% substitution of Ti4+ for Fe3+, which is believed to arise from the disruption of the spiral spin modulation after structural modification, and the interaction between the spins of the Dy3+ and Fe3+ at low temperatures which decouples the antiferromagnetic order between the Fe3+ ions.