Affiliation:
1. Department of Physics, Indian Institute of Technology (BHU), Varanasi, India
Abstract
Ruddlesden-Popper oxide Sr2Mn0.7Sn0.3O4 was synthesized by solid state method
by calcining at different temperatures between 1200 and 1500?C. The phase
evolution during thermal treatments was investigated and it was shown that
the powder calcined at 1500?C and ceramics sintered at 1500?C have single
phase structure. Rietveld refinement of the XRD data confirmed tetragonal
crystal structure having a = b = 3.9425 ? and c = 12.1230? lattice
parameters and I4/mmm space group symmetry. Permittivity (?), impedance
(Z*), dissipation factor (tan ?) and AC conductivity (?AC) of the samples
were studied in the frequency range 1 kHz-2MHz and temperature range 60-600?C. An equivalent circuit comprising two parallel R-L elements and one
constant phase element (CPE) model fitted the impedance data very well.
Components of the equivalent circuit were correlated with compositional
micro inhomogeneities in the sintered sample. Resonance-like feature
observed in the dissipation factor at a particular temperature is attributed
to the cancellation of capacitive and inductive reactants. Negative
permittivity and loss of the sintered sample were compared with other
ceramic oxides showing negative permittivity.
Publisher
National Library of Serbia