Structure and Differentiated Electrical Characteristics of M1/2La1/2Cu3Ti4O12 (M = Li, Na, K) Ceramics Prepared by Sol–Gel Method

• Published in: Journal of electronic materials 2017-10, Vol.46 (10), p.6175-6187
• Main Authors: Liu, Zhanqing, Yang, Zupei
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Solid State Physics
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-017-5632-4

New M 1/2 La 1/2 Cu 3 Ti 4 O 12 (M = Li, Na, K) ceramics based on partial substitution of Li + , Na + , and K + for La 3+ in La 2/3 Cu 3 Ti 4 O 12 (LCTO) have been prepared by a sol–gel method, and the effects of Li + , Na + , and K + on the microstructure and electrical properties investigated in detail, revealing different results depending on the substituent. The cell parameter increased with increasing radius of the substituent ion (Li + , Na + , K + ). Li 1/2 La 1/2 Cu 3 Ti 4 O 12 (LLCTO) ceramic showed better frequency and temperature stability, but the dielectric constant decreased and the third abnormal dielectric peak disappeared from the dielectric temperature spectrum. Na 1/2 La 1/2 Cu 3 Ti 4 O 12 (NLCTO) ceramic exhibited higher dielectric constant and better frequency and temperature stability, and displayed the second dielectric relaxation in electric modulus plots. The performance of K 1/2 La 1/2 Cu 3 Ti 4 O 12 (KLCTO) ceramic was deteriorated. These different microstructures and electrical properties may be due to the effect of different defect structures generated in the ceramic as well as grain size. This work represents the first analysis and comparison of these remarkable differences in the electrical behavior of ceramics obtained by partial substitution of Li + , Na + , and K + for La 3+ in LCTO.