The CexLa1-xOy samples are synthesized, characterized and their electrical properties are reported at different molar ratios in the frequency range of 10(-1)-10(+5) Hz. Ac conductivity and permittivity data are analyzed by using conductivity formalism. The values of capacitance and tan(delta) were recorded with respect to different frequencies and temperatures. X-ray diffraction (XRD) patterns of the films show that the films posses crystalline phases. Surface morphology of the films is analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses reveal that elemental composition is in right stoichiometry. Electrical characterizations of the CexLa1-xOy samples were done by capacitance-voltage (C-V) and current density-voltage (J-V) measurements of MOS structures. Investigation showed high value of k=44.80 and low leakage current (similar to 1 x 10(-5) A/cm(2)) of the Ce0.4La0.6Oy film. (C) 2015 Elsevier Ltd. All rights reserved.