摘要
利用碘滴定法测定了钙钛矿型复合氧化物La1-xSrxCoO3 -δ系列样品中金属元素的平均价态及氧的非化学计量值。实验发现 :La1-xSrxCoO3 -δ样品中的Co元素的平均价态随Sr掺杂量x的增加先增后减 ,室温下 ,在x =0 .5时取最大值 ,温度升高 ,最大值移至x =0 .4处。实验还发现 ,样品的电导率和 330K时的内耗峰峰高随Sr掺杂量x的变化也有类似极值 ,且极值点也分别出现在 0 .4和 0 .5左右 ,表明复合氧化物La1-xSrxCoO3 -δ中的电子传导是通过极化子进行的。对于同一Sr掺杂量的样品 。
The average valence of Co ions and the oxygen nonstochiometry of perovskite-type oxides La 1-x Sr x CoO 3-δ were studied by means of iodometric titration. It has been found that the cobalt valence increases with the strontium content, goes through a maximum at x =0.5 and decreases with higher strontium content. At room temperature, the maximum appears at x=0.5 , and it shifts to x =0.4 when the temperature increases. The electrical conductivity and relaxation strengthof internal friction peak at 330K shows the similar variation pattern. For the same Sr dopant content, the average valence of Co decreases with the temperature.
基金
国家自然科学基金! (No .597892 0 1)
86 3新材料领域资助课题
关键词
平均价态
钙钛矿
金属复合氧化物
导体
缺陷
Iodometric titration, Average valence, Nonstoichiometry, Electric conductivity, Internal friction
