Lithium-lanthanum-zirconium-oxide (Li-La-Zr-O) thin films were deposited using radio-frequency (RF) magnetron sputtering by varying the RF power from 40 to 80 W. The characteristics are investigated with X-ray diffraction analysis (XRD) and Field Emission Scanning Electron Microscope (FE-SEM). Results showed that the thin films had amorphous structure accompanied with a smooth, dense, and homogeneous surface. Impedance analysis was conducted to investigate the ionic conductivity. The thin film deposited at 40 W gives the highest ionic conductivity of 4 x 10(-7) S/cm when compared to both the 60 W and 80 W samples which show the ionic conductivity of 2 x 10-7 S/cm and 0.8 x 10(-7) S/cm respectively. The temperature dependence of the ionic conductivities fit the Arrhenius relation and the thin film deposited at 40 W possessed the lowest activation energy. These properties make Li-La-Zr-O thin films as a promising candidate material for use in all-solid-state thin film lithium ion batteries. (c) 2012 Elsevier B.V. All rights reserved.