Analysis of point defects in polycrystalline BaTiO3 by electron paramagnetic resonance
Analysis of point defects in polycrystalline BaTiO3 by electron paramagnetic resonance
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DOI：
10.1016/s0022-3697(02)00454-7
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发表时间：
2003-06-01
影响因子：
4
通讯作者：
Petric, A
中科院分区：
文献类型：
--
作者：
Kolodiazhnyi, T;Petric, A
用电子顺磁共振技术检测和鉴定了钛酸钡多晶体中的几种顺磁点缺陷。在还原性气氛中烧结的多晶样品显示出宽信号，具有1.932的吉罗磁常数。这个信号，观察到只有在导电陶瓷，被分配到Ti 3+及其相关的配合物。V-Ba和V-Ti缺陷分别出现在1.974和2.004的几何常数处。在T > 1000 ℃氧化后，这些缺陷的EPR强度增加。氧化陶瓷EPR谱中出现的V-Ba和V-Ti信号与PTCR效应的开始有关。在施主掺杂剂水平大于或等于0.3at.%时，V-Ba和V-Ti的浓度与施主掺杂BaTiO_3的缺陷补偿机制有很好的一致性。然而，在未掺杂的钛酸钡中也检测到少量的V-Ba和V-Ti，与普遍接受的缺陷模型相反。(C)2003爱思唯尔科技有限公司版权所有。
Several paramagnetic point defects in BaTiO3 Polycrystals were detected and identified using the electron paramagnetic resonance technique. Polycrystalline samples sintered in a reducing atmosphere showed a broad signal with a giromagnetic constant of 1.932. This signal, observed only in conducting ceramics, was assigned to Ti3+ and its related complexes. V-Ba and V-Ti defects were found at giromagetic constants of 1.974 and 2.004, respectively. The EPR intensity of these defects increases after oxidising at T > 1000degreesC. The appearance of the V-Ba and V-Ti signals in EPR spectra of oxidized ceramics correlates with the onset of the PTCR effect. At donor dopant levels greater than or equal to0.3 at.%, the concentration of V-Ba and V-Ti shows good agreement with the defect compensation mechanism of donor doped BaTiO3. However, small amounts of V-Ba and V-Ti were also detected in undoped BaTiO3, contrary to the generally accepted defect model. (C) 2003 Elsevier Science Ltd. All rights reserved.