摘要
Rietveld refinement analysis indicates that A_(2)ErTaO_(6)(A=Sr^(+2),Ca^(+2)ceramics prepared by a solid-state route are crystallized in monoclinic perovskite phase with space group P21=n.Raman scattering and infrared spectroscopy are used to investigate the structure and phonon modes of the samples.Using Lorentzian lines,we have fitted the Raman spectra and the major Raman modes are assigned.Phonon vibrational frequency is modulated with the A-site cationic change.Impedance spectra of the samples over the frequency range of 100 Hz–1.1 MHz are investigated at different temperatures from 303 K to 573 K.Cole–Cole relaxation of dielectric constant is modified with the electrical conduction parameter to describe the temperature dependence of dielectric constant.The frequency-dependent conductivity spectra follow the double power-law.
基金
the University Grants Commission(UGC)for award of Teacher Fellowship[No.F.TF.WB-010-02/13-14(ERO)]under the College Faculty Development Programme.Alo Dutta thanks the Department of Science and Technology of India for providing the finan-cial support through DST Fast Track Project under the Grant No.SR/FTP/PS-175/2013.
