Intrinsic Co⁴⁺/Co²⁺ defect formation in late members of the perovskite rare earth metal cobaltate oxide series as evidenced by dielectric relaxation measurements

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• 作者：S.L.L.M. Ramos^a ; ^{ramos.s.aa@m.titech.ac.jp} ; R. Sawano^b ; M. Oguni^a ; Y. Masuda^c
• 关键词：Rare earth cobaltate perovskites ; Co4+ and Co2+ intrinsic defects ; Dielectric relaxation ; Electric modulus ; Glassy state of polarons ; Non-Arrhenius
• 刊名：Thermochimica Acta
• 出版年：2012
• 期刊代码：110_00406031
• 类别：ch
• 出版时间：20 March, 2012
• 卷：532
• 期：Complete
• 页码：187-189
• 文件大小：266 K

摘要

The ac dielectric response of GdCoO₃ and HoCoO₃ was investigated. Dielectric relaxations were observed in the imaginary part of the electric modulus M鈥?for both compounds. The relaxation times obeyed an Arrhenius relationship in HoCoO₃, whereas they did not in GdCoO₃. The behavior has been discussed in terms of polaron hopping accompanying the Co⁴⁺ species, suggesting the electrical transport mechanism to be similar to that in LaCoO₃. The calorimetric relevance to the rearrangement of the polaron in HoCoO₃ has also been referred to as compared to that in GdCoO₃ and LaCoO₃.