A study of the intrinsic and extrinsic defects in BaTiO3 using electron paramagnetic resonance
碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 102 === A commercial BaO-excess BaTiO3 powder added with 3.0 mol.% CaTiO3 and 5.0 mol% MgO and sintered under low pO2 is studied for the extrinsic defect behavior through electron paramagnetic resonance (EPR). The composition resembles a formulation for making EIA-...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2014
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| Online Access: | http://ndltd.ncl.edu.tw/handle/akfm7n |
| Summary: | 碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 102 === A commercial BaO-excess BaTiO3 powder added with 3.0 mol.% CaTiO3 and 5.0 mol% MgO and sintered under low pO2 is studied for the extrinsic defect behavior through electron paramagnetic resonance (EPR). The composition resembles a formulation for making EIA-X7R base-metal-electrode multilayer ceramic capacitors (BME-MLCC). Two characteristic EPR lines at g = 1.974 and g = 2.004 are assigned to Ti-vacancy and Ba-vacancy forming complex defects with O-vacancy, respectively. The EPR line at g = 1.974 also appears in SrO-exess SrTiO3 reinforces the claim that the corresponding paramagnetic sensitive defect is associated with Ti-vacancy. Both room-temperature and low-temperature (77 K) cathodoluminiscence (CL) spectra are obtained to support the defect species assigned to EPR lines. Extrinsic oxygen vacancies generated by low-pO2 and by the acceptor-doping level in the BaO-excess BaTiO3 composition when sintered at 1200oC and 1000oC are charge-compensated by cation vacancies, principally by Ti-vacancies.
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