层状钙钛矿结构铁电薄膜SrBi_2Ta_2O_9的掺杂改性研究

DOPING CHARACTERIZATION STUDIES OF LAYERED PEROVSKITE SrBi 2Ta 2O 9 FERROELECTRIC THIN FILMS *

研究了Ｎｂ掺杂对层状钙钛矿结构铁电薄膜ＳｒＢｉ２Ｔａ２Ｏ９（ＳＢＴ）的改性，分析了其改性机理．利用光声光谱技术对不同含量Ｎｂ掺杂ＳＢＴ薄膜的可见光吸收进行了分析．结果表明掺杂ＳＢＴ薄膜在５８０ｎｍ处的吸收带随Ｎｂ含量的增加发生红移，这暗示掺杂ＳＢＴ薄膜的能隙与Ｎｂ含量有关．对掺杂ＳＢＴ薄膜的铁电性质研究表明，薄膜的剩余极化值依赖于薄膜中的Ｎｂ含量。

Abstract  The characterization of Nb doped layered perovskite SrBi 2Ta 2O 9 was studied.The mechanism of modification of properties was analyzed.Photoacoustic spectroscopy has been used to study the light absorption of SrBi 2Ta 2O 9 with various Nb contents.The results show that the absorption band at 580nm in the photoacoustic spectroscopy exhibits a red shift with increasing niobium content.The remanent polarization of Nb doped SrBi 2Ta 2O 9 films depends on the concentration ratio of Ta/Nb.The remanent polarization of the films arose an maximum at the area of Ta/Nb≈1.This may be related to the existence of morphotropic phase boundary. 