$(Ba, Sr)TiO_3$계 PTCR 세라믹스의 입계산화에 대한 $\mu-AES$ 분석 및 $DV-X\alpha$ 궤도에너지 계산모사 = Analysis of Grain Boundary Oxidation in $(Ba, Sr)TiO_3$-based PTCR Ceramics by $\mu-AES$ and $DV-X\alpha$ Energy Simulation

다국어 초록 (Multilingual Abstract)

(Ba, Sr)TiO3-based PTCR ceramics were sintered and cooled down with various cooling conditions in the air. AES was applied to investigate the composition change in the grain boundary and bulk area of oxidatively cooled samples. Ba component was deficit in grain boundary region, while oxygen was abundant than bulk region. The discrete changes of oxygen binding energies were confirmed in the grain boundary region of the heavily oxidized samples. It was supposed that the large binding energy shift resulted from the oxidation of the segregated Mn in grain boundary region and this idea was supported by the DV-X$\alpha$ molecular energy simulation.