Crystal symmetry and magnetism in Ti substituted Bi0.8Ba0.2FeO3 ceramic

The effect of Ti4+ substitution on the crystal structure and magnetic properties of the Bi0.8Ba0.2FeO3 ceramic nanoparticles was investigated. Bi0.8Ba0.2Fe1-xTixO3 (x=0, 0.05, 0.10, 0.15 and 0.20) ceramics have been prepared by tartaric acid modified sol-gel method. Rietveld refinement of the XRD profile pattern of Bi0.8Ba0.2FeO3 ceramic revealed the formation of pseudo-cubic (Pm3m) phase and confirms structural distortion on incorporation of Ti4+ ions, which consequently transform pseudo-cubic (Pm3m) structure to tetragonal (P4mm) structure. The saturation magnetization increases appreciably on Ti4+ ions substitution in Bi0.8Ba0.2FeO3 and is found to be 0.57 emu/g for Bi0.8Ba0.2Fe0.95Ti0.05O3 ceramic. The increase in the magnetization by the substitution of non-magnetic Ti4+ ions has been ascribed to crystal structure modification made by the Ti4+ ions. However, a sudden decrease in the magnetization has been observed for Bi0.8B0.2Fe0.8Ti0.2O3 ceramic nanoparticles. The prominent Ti (3d) - O (2p) hybridization would stabilize the ferroelectric distortion and consequently reduce the magnetization. Scanning Electron Microscope (SEM) image of Bi0.8Ba0.2Fe0.8Ti0.2O3 ceramic sample revealed the formation of dense microstructure with uniform grains size.