Investigation into defect chemistry and relaxation processes in niobium doped and undoped SrBi₄Ti₄O₁₅ using impedance spectroscopy.

ABSTRACT: The aurivillius family of compounds SrBi₄Ti₄O₁₅ (SBTi) and SrBi₄Ti_3.8Nb_0.2O₁₅ has been prepared using solid state reaction techniques. The niobium doping enhances the value of the dielectric constant, but decreases the phase transition temperature and grain size of SBTi. Grain conductivity evaluated from the impedance data reveals that Nb doping increases the resistance of grains which indicates the decrease in oxygen vacancies. The negative temperature coefficient of resistance shown by the grain boundary conductivity is explained using the Heywang-Jonker model. The variation of ac conductivity with frequency is found to obey Jonscher's universal power law. The frequency exponent (n), pre-exponential facto

SUBMITTER: Jose R 

PROVIDER: S-EPMC9087022 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature