Study is devoted to the effective relative permittivity epsilon(r) of CeO2 + x. Sm2O3 thin films prepared by electron-beam physical vapour deposition and ionic beam-assisted deposition methods; epsilon(r) was investigated by three independent ways from the bulk parallel capacitance C-p, impedance capacitance C-imp, and accumulation capacitance C-acc in dependence on the deposition conditions (deposition temperature, dopant amount x and Ar+ ion bombardment during the film deposition) used. Investigations were performed using impedance spectroscopy, capacitance-voltage and current-voltage characteristics as well as deep level transient spectroscopy. Results obtained are described and discussed. (C) 2012 Elsevier B. V. All rights reserved.