Influence Of BiFeO3 Addition On The Electrical Properties Of (Na, K) (Nb, Ta)O3 Ceramic System Using impedance Spectroscopy

Ferroelectric Research Laboratory, Department of Physics, A. N. College, Patna 800013, India

Adv. Mater. Lett., 2014, 5 (11), pp 658-665

DOI: 10.5185/amlett.2014.3600

Publication Date (Web): Nov 09, 2014

Copyright © IAAM-VBRI Press

E-mail: seema_sharma26@yahoo.com

Abstract

Polycrystalline samples of 1- x(Na0.5 K_0.5)(Nb_0.95 Ta_0.05) ) -x(Bi Fe)O₃ with x=0, 0.003, 0.005, 0.007) hereby denoted as NKNT-BF were prepared by the mixed oxide method. Preliminary structural studies carried out by X-ray diffraction technique showed the formation of perovskite structure with orthorhombic symmetry. Addition of BF in the NKNT system lowered the sintering temperature by 500C. The nature of the frequency dependence of ac conductivity of NKNT compounds follows Jonscher power law. Complex impedance and modulus spectra confirm the significant contribution of both grain and grain boundary to the electrical response of the materials. Above the ferroelectric–paraelectric phase transition temperature, the electrical conduction is governed by the thermal excitation of charge carriers from oxygen vacancies exhibiting Negative temperature coefficient (NTCR) behaviour. Detailed study on the multiferroic properties (where magnetism and ferroelectricity are strongly coupled together) of the system is under process which is likely to form key components in the development of future technology, for example, in memories and logic devices.

Keywords

Ceramics, sintering, powder diffraction, electrical conductivity