Investigations on the effect of Ba and Zr co-doping on the structural, thermal, electrical and magnetic properties of BiFeO3 multiferroics

Abstract

Effect of net-charge compensated aliovalent Ba and Zr co-doping on structure, thermal, electrical and magnetic properties of Bi1-xBaxFe1-xZrxO3 (x ≤ 0.10) samples has been investigated to improve ferroelectric and magnetic properties at room temperature. A pure phase formation with a rhombohedrally distorted perovskite structure was evidenced from X-ray diffraction patterns. Bond lengths and angles of FeO6 octahedron were calculated from Rietveld refinement data. Presence of metal-oxygen (Fe-O) absorption band was confirmed through IR spectra and bond lengths were also calculated from IR spectral frequencies. Curie temperature was found to decrease to 733 °C for x = 0.10 which is inversely correlated to tolerance factor. Decrease in length and the straightening of Fe–O–Fe bond angle of the octahedron led to partial suppression of spin cycloid which resulted in an increase of net magnetization. Increase in both polarizations (2Pr = 0.28 μC/cm2) and magnetization (2Mr = 21.8 memu/g) while retaining the rhombohedral crystal system without defects was the main outcome of Ba-Zr co-doped phase pure samples which are comparable to that of the reported value of Y-Zr and Ba-Ti co-doped BiFeO3 samples respectively.