Influence of rare-earth elements doping on structure and optical properties of BiFeO ₃ thin films fabricated by pulsed laser deposition

The Bi _1-x Eu _x FeO ₃ (BEFO _x , x = 0, 0.03, 0.05, 0.07, 0.1) films were grown on LaNiO ₃ coating Si substrates by pulsed laser deposition. X-ray diffraction patterns indicate that the films exhibit a (1 0 0)-highly oriented pseudocubic perovskite crystal structure. Scanning electron microscopy exhibits that the number of island-like structures decreases with increasing Eu dopant. The position of the A ₁ -1 mode of the films in the Raman spectra shifts to higher wavenumber with increasing x. With increasing the amount of Eu, the refractive index increases and the extinction coefficient decreases. In addition, the band gap of BEFO _x films decreases with increasing Eu dopant.