Study of Structural and Dielectric Properties of Nb5+ Doped Bi0.80Ca0.20FeO3 Ceramic

Abstract

A Ca
2+
and Nb
5+
modified Bi0.80Ca0.20Fe0.98Nb0.02O3 system
have been fabricated via solid-state route. The phase transitional behavior,
temperature and frequency dependent dielectric properties were
investigated for the understanding of the effect of co-substitution. X-ray
diffraction and Rietveld refinement confirmed the phase transformation
from rhombohedral symmetry. The synthesized perovskite structure has
combined effect of rhombohedral and orthorhombic phase. The electric
behavior of proposed sample was analyzed by impedance spectroscopy
over a wide range of frequency 1 Hz-7 MHz. The combined effect of
temperature and frequency revealed that dielectric parameters gradually
increased with temperature and reduced with a rise in frequency. The
frequency dependent dielectric analysis reflects that ɛʹ and tan δ possess
dispersion at lower frequency range. The studies of ac conductivity
reflected that system obeys Jonscher’s universal power law.
Temperature-dependent behavior of frequency exponent ‘s’ recommends
that correlated barrier hopping (CBH) model is appropriate for
describing conduction mechanism in the present system.