Effect of Mn doping on multiferroic properties in Bi0.8Ba 0.2FeO3 ceramics

Multiferroic ceramics Bi0.8Ba0.2Fe1-xMnxO3 with x=0.0, 0.05, 0.1, and 0.15 were prepared by using conventional solid state reaction method. The structural, magnetic, ferroelectric and dielectric properties were investigated. The phase transition from rhombohedral to tetragonal structure with increasing Mn substitution concentration was confirmed by using X-ray diffraction. Magnetic measurements indicated that the remanent magnetization of Bi0.8Ba0.2Fe0.95Mn0.05O3 (x=0.05) is around 2.64 times higher than that of Bi0.8Ba0.2FeO3 (x=0.0), which is probably due to the coexistence of rhombohedral and tetragonal phase that destructs the cycloidal spin structure and enhances the ferromagnetic properties significantly. The ferroelectric measurements revealed that the leakage current is significantly suppressed with an increase in the Mn content. In addition, Mn doping was found to be helpful to reduce dispersion in dielectric constant and loss, especially at lower frequencies. Furthermore, an anomaly in the dielectric constant was observed in the vicinity of the magnetic transition temperature, which could be attributed to the intrinsic magnetoelectric coupling effect. It is also worth noting that the intensity of the dielectric anomaly peak for the sample of x=0.05 was highest (similar to 183.4) among all the samples, which indicated that the magnetoelectric coupling effect could be greatly improved by enhanced ferromagnetic properties. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.