Ferroelectric, piezoelectric, and leakage current properties of (K₀.₄₈Na₀.₄₈Li₀.₀₄)(Nb₀.₇₇₅Ta₀.₂₂₅)O₃ thin films grown by pulsed laser deposition

Abstract

Lead-free K₀.₄₈Na₀.₄₈Li₀.₀₄ Nb₀.₇₇₅Ta₀.₂₂₅ O₃ (KNLNT) thin films were deposited on Pt(111)/Ti/SiO₂/Si(001) substrates using pulsed laser deposition. The film exhibited a well-defined ferroelectric hysteresis loop with a remnant polarization 2P[sub r] of 22.6 µC/cm² and a coercive field E[sub c] of 10.3 kV/mm. The effective piezoelectric coefficient d[sub 33,f] of the KNLNT thin films was found to be about 49 pm/V by piezoelectric force microscope. The dominant conduction mechanisms of Au/KNLNT/Pt thin film capacitor were determined to be bulk-limited space-charge-limited-current and Poole–Frenkle emission at low and high electric field strengths, respectively, within a measured temperature range of 130–370 K.