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

Ceramic samples of [Na0.5K0.5]1 − x(Li)x(Sb)x(Nb)1 − xO3 (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.

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► [Na0.5K0.5]1 − x(Li)x(Sb)x(Nb)1 − xO3 were prepared by solid-state reaction method.
► XRD analysis of the powder suggests the formation of a single-phase material.
► The crystal structure changes from orthorhombic to tetragonal with increase in x.
► Dielectric studies show a diffuse phase transition at 100 °C and 330 °C.
► The composition x = 0.050 shows maximum remanent polarization (Pr ∼ 0.66 C m−2).