(Na0.8K0.2)0.5Bi0.5TiO3 thin film: A Pb-free MPB composition with large piezoelectricity

A Pb-free ferroelectric (Na0.8K0.2)0.5Bi0.5TiO3 (NKBT) thin film is deposited on Pt/Ti/SiO2/Si(100) substrate at 650 °C using pulsed laser deposition technique. This NKBT film is characterized using scanning electron microscopy, x-ray diffraction, Raman spectroscopy, piezoresponse force microscopy, dielectric spectroscopy and PE-loop tracer. The dielectric and ferroelectric properties measured at 1 kHz yields a dielectric constant e ∼564, remnant polarization Pr ∼5.5 µC/cm2 and coercive field Ec ∼33.7 kV/cm. A high piezoelectric constant d33* ∼134 pm/V of NKBT film makes it suitable for a variety of electromechanical devices.