外加电场对铁电薄膜相变的影响  

Effect of external electric field on phase transitions of ferroelectric thin films

作　　者：吕业刚[1,2] 梁晓琳[1] 龚跃球[2] 郑学军[2] 刘志壮[1] 

机构地区：[1]湖南科技学院电子工程系,永州425100 [2]湘潭大学材料与光电物理学院,湘潭411105

出　　处：《物理学报》2010年第11期8167-8171,共5页Acta Physica Sinica

基　　金：国家杰出青年科学基金(批准号:10825209)资助的课题~~

摘　　要：采用热力学非线性理论,研究了外加电场对立方基底Pb(Zr0.3Ti0.7)O3(PZT)铁电薄膜相变的影响.通过数值计算,得到了"失配应变-外加电场"相图,及外加电场与极化强度的关系.当外加电场达到186kV/cm时,能使生长在SrTiO3基底上PZT铁电薄膜从单斜r相转变为c相.在实验上,采用扫描探针显微镜通过对PZT薄膜施加不同的极化电场来研究了它的电畴翻转.从得到的压电响应相图可以看出,绝大多数的电畴是清晰可见的.当外加极化电场达到200kV/cm时,处于单斜r相的电畴被翻转到c相的极化方向,这与前面理论计算的结果比较符合.A nonlinear thermodynamic theory is used to investigate the effect of external electric field on the phase transitions of Pb（Zr0.3 Ti0.7 ） O3 （PZT） thin films epitaxially grown on dissimilar cubic substrates.The ＂misfit strain-external electric filed＂phase diagram and the relationship between electirc filed and polarization are constructed for PZT thin films.The external electric field can transform the monoclinic r phase into the c phase,when its value reaches 186 kV/cm for PZT thin film grown on the SrTiO3 substrate.On the other hand,the domain switching of PZT thin film is investigated experimentally by scanning probe microscopy （SPM） via varying the applied polarizing electric field.The piezo-phase images reveal that most ferroelectric domains are clearly detectable.In the r phase,the domains can be reversed into the direction of polarization of the c phase,when the applied electric field increases to 200 kV/cm,which is close to the theoretical value （186 kV/cm）.

关 键 词：铁电薄膜 相变 扫描探针显微镜 失配应变 

分 类 号：O484.2[理学—固体物理]