Effects of SrTiO3 content and Mn doping on dielectric and magnetic properties of BiFeO3-SrTiO3 ceramics

Abstract

Perovskite BiFeO3-SrTiO3 ceramics have been prepared using solid-state reactions. Also, effects of SrTiO3 content on the crystal structure and magnetic properties of a BiFeO3-SrTiO 3 system have been studied. Single-phase perovskite BiFeO 3-SrTiO3ceramics have been fabricated/ Pure BiFeO 3 ceramics contain a small amount of a second phase, such as Bi 36Fe2O57 in perovskite BiFeO3. The crystallographic symmetry of BiFeO3-SrTiO3 changes from rhombohedral to cubic when SrTiO3 exceeds 20 mol%. Moreover, Mn doping to BiFeO3-SrTiO3 is very effective in controlling the grain growth and improving the sintered density. In particular, dielectric loss for the resultant ceramics is greatly reduced by Mn doping. The rhombohedrally distorted 0.9BiFeO3-0.1SrTiO3 shows a high Curie temperature (> 750°C) and weak ferromagnetism at 10-300 K. © 2009 The Ceramic Society of Japan.