应变对铁酸铋外延薄膜结构和压电性能的调控

Structure and piezoelectric properties of epitaxial BiFeO_3 thin films modulated by strain

在掺铌钛酸锶单晶衬底上,用脉冲激光沉积法制备不同厚度的铁酸铋外延薄膜,获得不同应变状态的铁酸铋薄膜,研究应变对薄膜结构和压电性能的影响.X线衍射结果显示铁酸铋薄膜沿衬底外延生长,并且随着厚度的增加,晶格弛豫,面外应变由2.778%减小到2.045%,铁酸铋薄膜也从完全应变过渡到应变部分释放.压电力显微镜测试显示,不同应变状态的铁酸铋薄膜都具有良好的压电响应,压电系数d33随应变的减小也相应地由259 pm/V减小到136 pm/V.

Epitaxial BiFeO3thin films of various strain states were grown on Nb SrTiO3substrate by pulsed laser deposition,the strain effects on crystal structure and piezoelectric properties of thin films had been investigated.X-ray diffraction results showed that BiFeO3thin films were epitaxially grown along the substrate orientation.The out of plane strain in BiFeO3thin films decreased from2.778%to2.045%with the increase of thickness,BiFeO3thin films also evolved from full strained to a partially relaxed one.Piezoresponse force microscopy measurements revealed that all the as grown BiFeO3thin films possessed high piezoelectric response and the piezoelectric coefficient d33decreased from259pm/V to136pm/V with the decrease of the film thickness.