Room-temperature multiferrocity and magnetodielectric properties of ternary BiFeO3–Bi0.5Na0.5TiO3–CaTiO3 ceramics across the rhombohedral–orthorhombic phase boundary

Abstract

A novel ternary solid solution (1-y)((1-x)BiFeO3–xBi0.5Na0.5TiO3)–yCaTiO3 (0\u2009≤\u2009x\u2009≤\u20090.3, 0.15\u2009≤\u2009y\u2009≤\u20090.25) is designed to present a rhombohedral–orthorhombic morphotropic phase boundary (MPB) with enhanced ferroelectricity, canted ferromagnetism, and room-temperature magnetoelectric responses. The addition of Bi0.5Na0.5TiO3 can generate a distinct MPB region and make BiFeO3–CaTiO3-based ceramics more denser. Therefore, superior ferroelectric properties with the remanent polarization of 37µC/cm2 can be obtained in the x\u2009=\u20090.3, y\u2009=\u20090.15 sample with the presence of rhombohedral–orthorhombic MPB. However, weak ferromagnetism is observed in both the rhombohedral and orthorhombic phases due to a destruction of the spiral spin structure of BiFeO3. The MPB with canted ferromagnetism is constructed. The maximum magnetoelectric interaction constant is found in the MPB compositions with x\u2009=\u20090.2, y\u2009=\u20090.2 which is related with the multiferroic phase boundary.