Doping effects of Li–Sb content on the structure and electrical properties of [(Na0.5K0.5)1−x(Li)x(Sb)x(Nb)1−xO3] lead-free piezoelectric ceramics

Abstract Ceramic samples of [Na 0.5 K 0.5 ] 1 − x (Li) x (Sb) x (Nb) 1 − x O 3 (NKNLS) ( x = 0.04–0.06) were prepared by high temperature solid-state reaction method. X-ray diffraction analysis of the powder samples suggests the formation of a single-phase material with transformation from orthorhombic to tetragonal crystal structure with increase in Sb content. Dielectric studies show a diffuse phase transition about 100 °C and another phase ferroelectric–paraelectric transition at 330 °C. Polarization vs. electric field ( P – E ) hysteresis studies show maximum remanent polarization ( Pr ∼ 0.66 C m −2 ) for composition x = 0.05. AC conductivity in the compound increases with increase in temperature which may be attributed due to oxygen vacancies and show negative temperature coefficient of resistance (NTCR) effect.