| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 101 === Strontium barium niobate ( SBN ) ceramic is a good electro-optic material. It has Tetragonal Tungsten Bronze (TTB) structure and SBN is a non centro-symmerty ferroelectrics. It has very high linear electro-optical coefficient、high pyroelectric coefficient and good photorefractive effect, SBN ceramic uses CZ method to growth now. Though the properties of the SBN single crystal has been intensively studied, its high cost and difficult fabrication have limited its practical use, such as shape, size or mechanical strength，hence it is necessary to develop polycrystal SBN ceramic.
We take advantage of Cole-Cole plot to study the dielectric properties and domain wall dynamics of pure SBN50 and co-doping Cr2O3,CeO2 under ac field, and analyze effects of different temperature and doping ratio, then we use function to fit the region of relaxation.
Finally, we observe the effect of co-doping in SBN50 by the fitting parameters.
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