(Pb0.76Ca0.24)TiO3薄膜电畴反转行为的压电力显微镜研究

Piezoresponse force microscopy studies of domain switching behavior in(Pb_(0.76)Ca_(0.24))TiO_3 thin films

用溶胶-凝胶法在(Pt/Ti/SiO2/Si)衬底制备了(Pb0.76Ca0.24)TiO3(PCT)薄膜。利用扫描力显微镜(SFM)的压电响应模式(PFM)观测了PCT薄膜的纳米尺度畴结构。畴结构和晶粒尺寸相关,尺寸在100 nm左右的晶粒表现为单畴,尺寸较大的晶粒表现为多畴。利用压电力显微镜研究了PCT薄膜中电畴的极化反转行为。通过SFM探针对畴施加一系列直流偏压极化,在每次极化后,利用压电响应模式扫描进行压电力成像,获得了与极化电压相关的畴反转信息。用探针施加电压对薄膜极化后,在不同的时间进行压电力成像,研究了电畴的退极化行为。

（Pb0.76 Ca0.24 ） TiO3 （PCT） thin films were prepared on Pt/Ti/SiO2/Si substrates by sol-gel spin coating method. Piezoresponse force microscopy was used to observe the nanoscale domain structure. It was found that domain structure was relevent to the size of the grains. The small grains （ -100 nm） presented as single domain while the large ones as polydomain structure. The strip domain structure was observed in the PCT film. The different width between the strip domain structures can be explained as the different stress on the grains. Piezoresponse force microscopy was used to perform nanoscale studies of the switching and back-switching processes via the direct observation of their domain structures.