Defect mediated magnetism in CO based BaTiO3 ferroelectric

Ceramic samples of BaTi0.95−xHf0.05CoxO3 (where, x=0.05, 0.1, and 0.15) were prepared through a solid state reaction route and structure, morphology, magnetic and ferroelectric properties have been investigated. Defects play a key role in influencing magnetic as well as the electric properties in the above compositions. Magnetism observed in doped compositions is significantly depended upon Co ion concentration and oxygen vacancies. With increasing of Co ion concentration, the concentration of oxygen vacancies is increased and as a result of which enhanced magnetic effect is observed. The presence of oxygen vacancy forms defect-dipoles with Co and Hf. These defect-dipoles prominently influenced the polarization and coercive field in doped compositions. Although remnant polarization is decreased noticeably in doped compositions, but the ferroelectricity is observed well above room temperature. These results clearly demonstrate the importance of the contribution of defects for observation of room temperature multiferroic properties in Co based BaTiO3 ceramics.