Ho and Ti co-doped BiFeO3 multiferroic ceramics with enhanced magnetization and ultrahigh electrical resistivity

Bi0.9Ho0.1Fe0.95O3 and Bi0.9Ho0.1Fe0.9Ti0.05O3 ceramics were prepared and compared to reveal the effects of Ho and Ti codoping in BiFeO3. X-ray diffraction indicated that both ceramics had a high rhombohedral perovskite phase content, and microstructural analyses showed that the grains of the Bi0.9Ho0.1Fe0.9Ti0.05O3 ceramics were much smaller than those of Bi0.9Ho0.1Fe0.95O3. An electrical resistivity of more than 1 x 10(14) Omega.cm at room temperature, and a magnetic hysteresis loop with a remnant magnetization 2M(r) of similar to 0.485 emu/g were obtained for Bi0.9Ho0.1Fe0.9Ti0.05O3; both were much higher than those of Bi0.9Ho0.1Fe0.95O3. Changes in the defect subsystem of BiFeO3 induced by Fe-deficiency and (Ho, Ti) codoping are proposed as being responsible for the improvement in the properties.