Effect of Oxygen Annealing on Ferroelectricity of BiFeO3 Thin Films Formed by Pulsed Laser Deposition

概要

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In this study, BiFeO3 (BFO) epitaxial film was deposited on SrRuO3(100)/SrTiO3(100) substrates by pulsed laser deposition (PLD). Phase-pure BFO thin film was obtained by introducing a mask between the target and the substrate in the deposition chamber. The use of the mask brought about an improvement in the morphology. The surface roughness was changed from 47.8 to 7.7 nm rms roughness under conditions without and with the mask, respectively. The composition and the electrical properties of BFO thin films were examined before and after annealing the samples for 1 h in atmospheric pressure O2 gas at 600 °C. An improvement of the polarization–electric field ($P$–$E$) hysteresis curve was obtained when BFO film was annealed in an O2 atmosphere. O2 gas annealing resulted in a remanent polarization ($P_{\text{r}}$) value increase from 17 to 25 μC/cm2 at room temperature. At a low temperature (80 K), the BFO thin film annealed in an O2 atmosphere showed the highest $P_{\text{r}}$ of 142 μC/cm2. We also investigated the optimum measurement conditions of the $P$–$E$ hysteresis curve for BiFeO3.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2007-06-15