溶胶-凝胶法制备BiFeO_3多铁性薄膜及其电磁性能研究

Study on multiferroic and electromagnetic properties of BiFeO_3 films prepared by sol-gel method

采用溶胶-凝胶法在SiO2/Si基底上制备纯相BiFeO3多铁性薄膜.利用X射线衍射仪对不同退火温度的薄膜样品进行晶体结构的测定和分析,结果表明:样品为钙钛矿结构,并呈随机取向.在室温下测量500℃退火样品的电滞回线及其不同频率下的介电常数和介电损耗;当外加电场达到14×107 V/m时,剩余极化强度(Pr)和饱和极化强度(Ps)分别为10.12μC/cm2和14.62μC/cm2;当频率范围在1kHz～1MHz时,样品的介电常数和介电损耗基本稳定,且损耗较小.此外,在室温下测量薄膜的磁性能,M-H曲线表明样品具有铁磁性.

Single-phase multiferroic BiFeO3films were prepared on Pt/SiO2/Si substrates by a simple sol-gel method.X-ray diffraction technique was used to characterize the structure of the sample at different annealed temperatures.X-ray diffraction pattern showed that the samples were perovskite structure and randomly oriented.The dielectric constant and dissipation of different frequencies and the electric hysteresis loop of the samples annealed at 500℃ were measured at room temperature.When the external electric field reached to 14×107 V/m,remnant polarization（Pr）of 10.12μC/cm2 and saturation polarization（Ps）of 14.62μC/cm2 were identified.The film sample showed stable dielectric constant and dissipation between 1kHz and 1MHz,and the dissipation was lesser.In addition,ferromagnetic properties were presented by the measuring of M-Hloops for the samples at room temperature.