Preparation and characterization of BiFeO₃ thin films grown on LaNiO₃-coated SrTiO₃ substrate by chemical solution deposition

BiFeO₃ (BFO) thin films were grown by chemical solution deposition on SrTiO₃ (1 0 0) substrate. LaNiO₃ thin films were used as the bottom electrode. X-ray diffraction pattern indicated that the samples exhibited highly (1 0 0) oriented. Scanning electron microscopy showed that the BFO thin film possessed a dense microstructure and grains in BiFeO ₃ thin films were columnar. The remnant polarization of BFO thin films was 0.86 μC/cm² when 375 kV/cm electric field was applied at 80 K. The conductivities of the samples at room temperature and 80 K were smaller than 10^-12 Ω^-1 cm^-1. At 80 K, the permittivity of the BFO thin films decreased from 76 to 62 linearly with the frequency increasing from 1 kHz to 1 MHz. The dielectric loss was about 0.05 when the frequency was in the range of 1000-100 kHz, and was lower than 0.2 when the frequency was lower than 1 MHz. The pyroelectric coefficient at room temperature was 1.47 nC/(cm² K).