Low-frequency dielectric properties of CaNb2O6 ceramics over a wide temperature range. Issue 10 (December 2015)

• Record Type: Journal Article
• Authors: Li, Haibo; Wang, Chunchang; Wang, Hong; Zhang, Da; Zhang, Nan
• Is Part Of: Ceramics international. Volume 41:Issue 10(2015)Part B
• Page Start: 14773
• Page End: 14779
• Publication Date: 2015-12
• Subjects: Dielectric property -- Oxygen vacancy -- Impedance spectroscopic -- Electric modulus -- Conduction relaxation; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.07.209
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: CaNb2 O6 ceramics were prepared by a conventional solid-state reaction method. By means of the complex dielectric permittivity, electric modulus spectroscopy, and impedance analysis, the dielectric properties of CaNb2 O6 ceramics were investigated in the temperature range (180–1050 K) and frequency range (50–1×10 7 Hz). The sample exhibits an intrinsic dielectric response with a dielectric constant of 18.06 below 400 K. In the temperature range from 400 to 1023 K, the sample successively shows a relaxor-like peak and an increasing ramp. Annealing treatments in N2 and O2 atmospheres revealed that the relaxor-like peak is consisted of two different relaxations (R1 and R2) and the ramp is evidenced to be another relaxation (R3). Our results demonstrated that the low-temperature relaxation (R1) belongs to Maxwell–Wagner-type dielectric relaxation caused by surface-layer effect due to the inhomogeneous distribution of oxygen vacancies. The high-temperature relaxations R2 and R3 are conduction relaxation due to hopping motions of singly and doubly charged oxygen vacancies, respectively. A phase transition is revealed to have affinity relationship with oxygen vacancies and most possibly related to the transition of oxygen-vacancy-distribution from a static disorder state to a dynamic disorder state.