Naganuma H, Inoue Y, Okamura S
Department of Applied Physics, Tokyo University of Science, Tokyo, Japan.
IEEE Trans Ultrason Ferroelectr Freq Control. 2008 May;55(5):1046-50. doi: 10.1109/TUFFC.2008.754.
A multiferroic BiFeO(3) film was fabricated on a Pt/Ti/SiO(3)/Si(100) substrate by a chemical solution deposition (CSD) method, and this was followed by postdeposition annealing at 923 K for 10 min in air. X-ray diffraction analysis indicated the formation of the polycrystalline single phase of the BiFeO(3) film. A high remanent polarization of 89 microC/cm(2) was observed at 90 K together with a relatively low electric coercive field of 0.32 MV/cm, although the ferroelectric hysteresis loops could not be observed at room temperature due to a high leakage current density. The temperature dependence of the ferroelectric hysteresis loops indicated that these hysteresis loops lose their shape above 165 K, and the nominal remanent polarization drastically increased due to the leakage current. Magnetic measurements indicated that the saturation magnetization was less than 1 emu/cm(3) at room temperature and increased to approximately 2 emu/cm(3) at 100 K, although the spontaneous magnetization could not appear. The magnetization curves of polycrystalline BiFeO3 film were nonlinear at both temperatures, which is different with BiFeO3 single crystal.
采用化学溶液沉积（CSD）法在Pt/Ti/SiO₃/Si(100)衬底上制备了多铁性BiFeO₃薄膜，随后在空气中923 K下进行10分钟的沉积后退火。X射线衍射分析表明形成了BiFeO₃薄膜的多晶单相。在90 K时观察到89 μC/cm²的高剩余极化以及0.32 MV/cm的相对低的矫顽电场，尽管由于高漏电流密度在室温下未观察到铁电滞回环。铁电滞回环的温度依赖性表明，这些滞回环在165 K以上失去形状，并且由于漏电流，名义剩余极化急剧增加。磁性测量表明，室温下饱和磁化强度小于1 emu/cm³，在100 K时增加到约2 emu/cm³，尽管未出现自发磁化。多晶BiFeO₃薄膜的磁化曲线在两个温度下均为非线性，这与BiFeO₃单晶不同。
