Structure, ferroelectric and magnetic behavior in Mn doped 0.75 BiFeO3-0.25BaTiO3 ceramics

Abstract

Lead-free polycrystalline 0.75 BiFe 1-xMn xO3-0.25BaTiO3 (x = 0.00, 0.01, 0.02 and 0.03 hereby designated as BF-BT) ceramics were synthesized by high temperature solid state reaction technique. This study dwells on the role of Mn doping on the structure, ferroelectric and magnetic behavior of BF-BT ceramics. Structural phase analysis of the samples carried out by X-ray diffraction and Raman scattering measurements revealed single phase distorted perovskite structure with rhombohedral symmetry. No alteration in crystal structure was observed with increasing Mn concentration. The average crystallite size of the compounds increases (12.9–27.8 nm) with increasing Mn concentration. The saturated value of ferroelectric polarization (Pr) was found to decrease with increasing Mn-concentration and a maximum remnant polarization (Pr) of 0.6 μC/cm2 was recorded at an applied field of 25 kV/cm for x = 0.00 sample. Leakage current density was found to increase with increase in Mn concentration. Oxidation states of the cations probed by X-ray photoelectron spectroscopy (XPS) suggested that Fe/Mn were in mixed state (+3/+2), while Ti-ion demonstrated (+3/+4) state. Presence of multivalence states of Fe/Mn/Ti causing distortion in the lattice (attributed to Jahn Teller) with increasing Mn concentration significantly affects the magnetic behavior of the ceramics. A maximum value of saturation magnetization of Ms∼0.80emu/gm was recorded for x = 0.03 composition.