| Summary: | 碩士 === 國立成功大學 === 物理學系碩博士班 === 98 === In this study, I present a quantitative study of the 180 degree domain wall motion in epitaxial BiFeO3 films, and discuss the domain growth behaviors by the piezoresponse force microscopy (PFM). The topography, in-plane (IP), and out-of-plane (OP) components of domains for BFO thin films can be revealed simultaneously. The upward and downward activation field (αup and αdown) on BFO(001)/SRO/STO epitaxial thin film was about 2.601~ 2.895 MV/cm and 0.889~ 0.947 MV/cm, respectively. We suggest the as-grown 710 domain wall only had clip effects on dynamic behaviors of the domains. When the domain grew to the size about original domain width, the domain wall was clipped by the 710 domain wall. . In order to understand the polarization axis and the thickness effect under the dynamic process, we used two different samples, BFO(111)/SRO/STO and BFO(001)/SRO/DSO thin films. Finally, we created a screen charge model to support the activation behavior. The static electricity energy plays a critical role in the activation process.
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