Induced core-shell structure and the electric properties of (K 0.48 Na 0.52 ) 0.95 Li 0.05 Nb 0.95 Sb 0.05 O 3 ceramics

• Published in: Physical chemistry chemical physics : PCCP Vol. 19; no. 3; pp. 1868 - 1874
• Main Authors: Zhou, Min, Lu, Xiaomei, Yang, Dianyuan, He, Ju, Huang, Fengzhen, Mei, Fang, Ren, Xianming, Xu, Xingyu, Li, Yang, Zhu, Jinsong
• Format: Journal Article
• Language: English
• Published: England 18.01.2017
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/C6CP06111G

The relationship among dielectric anomaly, ferroelectric response, defects, and microstructures was established for (K Na ) Li Nb Sb O (x = 0.04, 0.00, -0.02, -0.04 and -0.08) ceramics. For x = -0.02 and -0.04, larger coercive fields and lower remnant polarizations were obtained; besides, an additional dielectric relaxation behavior was observed with the activation energy E being about 2.19 eV and 1.92 eV, respectively. Furthermore, the grain and grain boundary contributions to the capacitance were separated using impedance spectroscopy, which, combined with back-scattering characterization, firmly indicates the core-shell structure of K-deficient samples (x = -0.02 and -0.04). Unlike the cores, the shells possess a large amount of K vacancies (). This work paves a way for regulating the fine structure and more on the electrical properties of KNN-based materials.