Effect of Ta content on the phase transition and piezoelectric properties of lead-free (K0.48Na0.48Li0.04)(Nb0.995-xMn0.005Tax)O-3 thin film

Abstract

Lead-free (K0.48Na0.48Li0.04)(Nb0.995-xMn0.005Tax)O-3 (abbreviated KNL-NMT-x, x = 0 similar to 0.20) thin films were prepared using a chemical solution deposition method, and the effects of Ta content on the structural, dielectric, ferroelectric, and piezoelectric properties were investigated. X ray diffraction results indicate that the phase structure of KNL-NMT-x films undergoes a transition from orthorhombic to pseudocubic phase with increasing Ta content. The substitution of Ta5+ for the Nb5+ site in the KNL-NMT-x films produced to the relaxor-like ferroelectric with a diffuse phase transition. The KNL-NMT-0.10 thin film at the orthorhombic-pseudocubic phase boundary showed optimum dielectric and piezoelectric properties; dielectric constant epsilon(r) = 2650, Curie temperature T-c = 323 degrees C, remnant polarization P-r = 16.1 mu C/cm(2), coercive field E-c = 22.2 kV/cm, and effective piezoelectric coefficient d(33,f) = 61 pm/V. (C) 2012 American Institute of Physics. [doi:10.1063/1.3680882]