Authors: G Liu X Q Liu X M Chen
Publish Date: 2014/01/29
Volume: 116, Issue: 3, Pages: 1421-1427
Abstract
The dielectric properties of Sm15Sr05NiO4−δ ceramics with different concentrations of oxygen vacancies were characterized The ceramics with lower concentration of oxygen vacancies were prepared by directly sintering the sol–gel derived powders in air while the higher one could be obtained by annealing the assintered ceramics in the flow of nitrogen The postdensification annealing in the flow of nitrogen decreased the dielectric constant at low temperature and increased it at high temperature while the dielectric loss increased in overall temperature range The activation energy of lowtemperature dielectric relaxation decreased with increasing the concentration of oxygen vacancies and so did that of bulk electrical resistances although the values of resistances increased while the activation energy of electrical resistances for grain boundary increased though the values of resistances decreased The giant dielectric response in the assintered Sm15Sr05NiO4−δ ceramics should be mainly attributed to the small polaronic hopping process while that of annealed ceramics should be directly linked to the oxygen vacancies
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