High-temperature coulometric titration of La1-xSrxCoO3-δ : Evidence for the effect of electronic band structure on nonstoichiometry behavior
High-temperature coulometric titration of La1-xSrxCoO3-δ : Evidence for the effect of electronic band structure on nonstoichiometry behavior
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La1-xSrxCoO3-δ 的高温库仑滴定：电子能带结构对非化学计量行为影响的证据
DOI：
10.1006/jssc.1997.7531
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发表时间：
1997
影响因子：
5.4
通讯作者：
H. Verweij
中科院分区：
文献类型：
--
作者：
M. Lankhorst;Henny J. M. Bouwmeester;H. Verweij
通过高温氧库仑滴定法测量了钙钛矿 La1−xSrxCoO3−δ 中的平衡氧化学势以及 O2 的部分能量和熵，作为 δ 和 x 的函数。随着净电子浓度 2δ−x 的增加，观察到氧化学势几乎呈线性下降。观察到的行为被解释为反映了在用空位形成或降低 Sr 掺杂剂水平诱导的电子填充宽电子带中的状态时费米能级的相应增加。这些结果使得能够计算费米能级的表观态密度。对于低 δ 值和高温，La1−xSrxCoO3−δ 中的氧空位随机分布在等效氧位点之间。通过增加 δ 或降低温度，会产生对部分能量和熵的额外离子贡献，但这些会抵消氧空位的化学势。这些结果可能是由于氧空位排列成微域所致
The equilibrium oxygen chemical potential and the partial energy and entropy of O2in perovskites La1−xSrxCoO3−δwere measured as a function ofδandxby high-temperature oxygen coulometric titration. An almost linear decrease in the oxygen chemical potential is observed with increasing net electron concentration 2δ−x. The observed behavior is interpreted to reflect the corresponding increase in the Fermi level on filling up states in a broad electron band with electrons induced by vacancy formation or reducing the Sr-dopant level. The results enable calculation of the apparent density of states at the Fermi level. For low values ofδand high temperatures, the oxygen vacancies in La1−xSrxCoO3−δare randomly distributed among equivalent oxygen sites. By increasingδor by lowering the temperature, additional ionic contributions to the partial energy and entropy arise, but these cancel in the chemical potential of oxygen vacancies. These results are possibly due to ordering of oxygen vacancies into microdomains