Ferromagnetic Behavior of Undoped BiFeO3 Thin Films Prepared by Sol-gel

Synthesis of un-doped BiFeO3 sol is optimized using ethylene glycol as solvent. Optimally synthesized BiFeO3 sols are then spun onto Cu substrates to obtain films of thickness 100-300 nm. X-ray diffraction results show the formation of BiFeO3 even in the as-deposited samples. Annealing does not result in inclusion of bismuth rich or bismuth deficient phase in the films. The films show ferromagnetic behavior due to suppression of spiral spin arrangement as the crystallite size falls below 60 nm.