Mn掺杂BaTiO_3基PTCR陶瓷相变的EPR研究

EPR Investigation on the Phase Transition of Mn-Doped BaTiO_3 PTCR Ceramics

为了探索利用ＥＰＲ谱线对ＰＴＣＲ陶瓷的相变及ＰＴＣ效应的机制研究的可能性，本文对接 Ｍｎ的 ＢａＴｉＯ３基正温度系数热敏电阻（简称ＰＴＣＲ）陶瓷在 １２０～４５０Ｋ温度范围内的电子顺磁共振谱进行了研究．得出了 Ｍｎ２＋离子 ＥＰＲ信号强度、 ｇ因子值和超精细耦合常数｜Ａ｜值的温度分布，发现ＥＰＲ参数与ＰＴＣＲ陶瓷相变有明显的对应关系，并给出微观结构上的初步解释．研究表明ＥＰＲ谱线以及精细结构的分析可以为ＰＴＣＲ陶瓷的相变机制以及ＰＴＣ效应的机制研究提供新的途径．

The EPR (Electron Paramagnetic Resonance) spectra of Mn-doped BaTiO3 PTCR ceramics measured at 120 similar to 450K were studied. The signal intensity, the g factors and the hyperfine splitting constants /A/ of Mn2+ at different temperatures were calculated. The results show that these parameters obviously correspond to the different phases of BaTiO3 based PTCR ceramics. This research indicates that EPR method can provide a new way to study upon mechanism of phase transition for PTCR ceramics.