Bi1?xLaxFeO3 films on LaNiO3 bottom electrode by the sol?gel process

La-substituted Bi1?xLaxFeO3 films have been prepared on LaNiO3/SiO2/Si(1?1?1) substrates by the sol?gel process. The films with x = 0.00?0.20 were prepared at an annealing temperature of 600??C. X-ray diffraction patterns indicate that all films adopt R3m structure and different orientation with the increase in x. A Bi2Fe4O9 phase was identified in the films with x = 0.01 and 0.02. Cross section scanning shows that the thickness of the films is about 270?nm. Enhanced ferroelectricity at room temperature was observed by measuring the electric hysteresis loops. The film with x = 0.10 has the largest double remnant polarization of 4.40??C?cm?2. The double remnant polarizations are 3.35??C?cm?2, 3.20??C?cm?2 and 3.49??C?cm?2 for the films with x = 0.0, 0.05 and 0.2, respectively. Moreover, the films with x = 0.05?0.20 show enhanced dielectric property. Through the substitution of La, the leakage current density is reduced for the films with x = 0.05?0.20 and the films show decreased leakage conduction.