(1-x)Sr_2Bi_4Ti_5O_(18)-xBiFeO_3复合铁电薄膜的制备及性能研究

Preparation and Properties of BFO-SBTi Composite Ferroelectric Thin Films

用溶胶-凝胶法结合层层退火工艺制备出(1-x)Sr_2Bi_4Ti_5O_(18)-xBiFeO_3(SBFTi-x,x=0.1-0.4)系列薄膜,对样品进行分析研究,发现随着BFO取代量x的增加,SBFTi-x复合薄膜的铁电性能逐渐提高。当BiFO_3(BFO)的取代量为0.3,测试电场为931 KV/cm时,剩余极化强度2Pr=23.4μC/cm^2,矫顽场2Ec=28.0 KV/cm,漏电流密度较小。对薄膜样品的漏电流曲线进行线性拟合,发现当测试电场强度低于230KV/cm时,曲线的拟合斜率ɑ都接近于1,说明薄膜内部的漏电流导电机制是以欧姆传导(ɑ≈1)为主,而测试场强高于230 KV/cm时,其导电机制为FN隧道效应。

（1-x）Sr2Bi4TisO,-xBiFeO3（SBFTi-x, x=0.1-0.4） composite ferroelectric films were prepared with Sr2Bi4TisO8 and BiFeO, then thefilm samples were tested and studied. Compared to Sr2Bi4Ti50,8 （SBTi） films, with the increasing of BFO content, the SBFTi-x ferroelectricfilms performed better in ferroelectrics. When the substitution amount of BFO was 0.3, in the field of 931 KV/cm, the remnant polarizationand coercive field were 2Pr=23.4 C/cmz and 2Ec=28.0 KV/cm. With the increasing of BFO content, the leakage increased gradually; when thesubstitution amount of BFO was 0.3, the leakage current density was small. The linear fitting of the leakage current found that when the fieldis less than 230 KV/cm, all the fitting slopes are close to 1, which shows that the membrane leakage mechanism is prior to ohmic conduction（ctl）; when the field is higher than 230 KV/cm, the conductive mechanism is FN tunneling.