Spray pyrolysis deposited multiferroic BiFeO3 films

Abstract

BiFeO3 (BFO) films were prepared by nebulized spray pyrolysis technique on a single crystal LaAlO3 (001) substrate at ∼300 °C and annealing in oxygen at ∼550 °C for 1 h. In all films BFO is the majority phase having a rhombohedrally distorted structure with R3m symmetry and lattice parameters are a=3.96 Å and α=89.7°. Atomic force microscopy reveals smooth and dense surface morphology. Despite the G -type antiferromagnetic spin structure of BFO the present BFO show well-defined M-H loops and unexpected ferromagnetism as evidenced by large saturation magnetization, ∼125 emu/cc. The origin of anomalous ferromagnetism in the present films has been traced to the presence of nanometric Fe2 O3 embedded in the BFO matrix. © 2009 American Institute of Physics.