Influence of Ce and Ni co-doping on structural, optical and magnetic properties of BiFeO₃ thin films

Bi_0.9Ce_0.1Fe_1-xNi_xO₃ (xBCFNO, x=0, 0.03, 0.05, 0.07) thin films were fabricated on SiO₂ substrates by sol-gel process. X-ray diffraction patterns indicate that all films exhibit a distorted pseudo-tetragonal perovskite structure with a high degree of (012/110) preferred orientation and peak position deviation. The intensity of (012/110) peak changes with the change of x with a maximum value at x=0.05. Furthermore, the grain size become the biggest at x=0.05 revealed by scanning electron microscopy (SEM). The smallest band gap of xBCFNO films is 2.14 eV at x=0.03 measured by the optical transmission spectra. The magnetic hysteresis (M-H) loops show that the room-temperature ferromagnetism was enhanced with Ce and Ni co-doping.