Local structure and defect analysis of KVO3 doped BiFeO3–BaTiO3 ceramics facing conductivity, permittivity, and magnetic properties

Abstract

This study discovers the effects of KVO3 doping on BiFeO3–BaTiO3 regarding phase transitions, defect formation, and changes in electronic and magnetic behavior. The synthesized material (1-x-y)BiFeO3-xBaTiO3-yKVO3 with (x = 0.33, 0.38 and y = 0, 0.01) have pseudo-cubic structure, where the FeO6 octahedron was elongated in the z-axis, and Fe has an oxidation state of 3+ and 4+. The electrons in the 3d subshell initially showed a high spin state, transitioning to a low state after KVO3 doping. Further investigation identified phase transition Rhombohedral + Pseudo Cubic to Rhombohedral for FT33 at T∼100°C and Pseudo Cubic phase to Cubic phase for FT38 at T∼200°C. Conductivity at low temperatures ascribed to unbinding electrons, while the presence of defect-creating dipole strengthened the dipole polarization. The magnetization hysteresis of KVO3-doped samples significantly decreased due to the high spin state transformed to the low spin state of the 3d subshell of Fe in the octahedron FeO6.