Electrical, electromechanical and structural studies of lead potassium samarium niobate ceramics

Dielectric spectroscopy has been applied to investigate the electrical properties of tungsten bronze ferroelectric ceramics of Pb0.77K0.115Sm0.115Nb2O6 (Sm:PKN) over a wide frequency (45 Hz to 5 MHz) and temperature (35–600 °C) range. XRD analysis showed the lattice parameters, a = 17.731 Å, b = 18.035 Å and c = 3.843 Å. Determined the piezoelectric constants, Kp = 18%, Kt = 21%, d33 = 68, and quality factor (Qm) = 38, reveals the material may be useful for transducer applications. Similar peak positions of normalized electrical modulus and impedance plots indicate the long range conductivity in Sm:PKN. Cole–Cole plots observed to be non-Debye type with polydispersive in nature. Determined the coefficient A(T) = {a(T)S/L}, the exponent n(T) fitted the Jonscher's dielectric dispersion relations for ɛI with experimental data. Parameters n(T) and A(T) showed an anomaly at the vicinity of TC, respectively. dc and ac conduction activation energies are estimated from Arrhenius plots. Compared the results from different techniques, and discussed the conduction mechanism in the material.