Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1626028 | Journal of Alloys and Compounds | 2007 | 7 Pages |
Abstract
The La1âxKxCo1âxNbxO3 system was performed by conventional solid state reaction technique using metal oxides. By DSC analysis, the activation energy of crystallization of the powders with x = 0.3 is 388.4 kJ/mol. The crystal structure of the compound reveals a transition from rhombohedral to cubic, and then to orthorhombic structure as the amount of the potassium niobate (KNbO3) increases. It is found that the structure of the samples with x < 0.3 is similar to that of lanthanum cobaltate (LaCoO3), while at the compositions with 0.7 â¥Â x â¥Â 0.3, the structure transforms to cubic. Finally, with x â¥Â 0.7, the structures were similar to that of KNbO3. According to the results of selected-area-diffraction (SAD) patterns and X-ray diffraction (XRD) identifications, the lattice parameters were calculated. The direction of superlattice structure along [2 1 0] was found for x = 0.5 as identified from SAD patterns. The dielectric constants were measured with cubic structure. Dielectric constant (K) decreases with increasing x.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Tzu-Wei Huang, Yee-Shin Chang, Guo-Ju Chen, Yen-Hwei Chang,