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

Polycrystalline samples of 1- x(Na0.5 K0.5)(Nb0.95 Ta0.05) ) -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)