Assessment of effective-medium theories of ion-beam sputtered Nb<sub>2</sub>O<sub>5</sub>–SiO<sub>2</sub> and ZrO<sub>2</sub>–SiO<sub>2</sub> mixtures

Abstract

Single-layer mixture coatings of ZrO2–SiO2 and Nb2O5–SiO2 produced by the ion beam sputtering (IBS) deposition technique were investigated in detail. Effective medium approximation (EMA) models and two non-optical methods, namely Rutherford backscattering spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS) were applied for characterization of elemental composition of these films. The comparison of obtained results indicates discrepancies in atomic material concentrations. The reasons and potential sources of such discrepancies are discussed qualitatively and indicate limitations of optical models.