Structure, magnetic and electrical properties of Ba-modified Bi2Fe4O9

Bi2-xBaxFe4O9 material (0x0.125) has been synthesized by sol-gel method. Structural characterization shows the single phase of orthorhombic Bi2Fe4O9. Moreover, the structure of Bi2-xBaxFe4O9 gradually presents a regular variation with increasing Ba content. Surface morphology of the samples is examined showing homogeneous grain distribution accompanied by the decreasing grain size with increase of Ba. Due to doping Ba, magnetic properties are significantly enhanced shown as the increasing remnant magnetization and saturation magnetization. Dielectric constant shows the increasing tendency with colossal values especially at high temperature range. In addition, the real part of ac conductivity exhibits the increasing trend with increasing frequency and the content of Ba. The analysis of impedance spectrum also suggests the increasing conductivity. The improvement in magnetic and electrical properties of Bi2Fe4O9 by substitution of Ba can be attributed to the different ionic radius of Ba2+ from Bi3+ to Fe3+ which results in the change of magnetic structure and morphology.