Effect of crystallographic structure on electrical and mechanical characteristics of Sm2O3-Doped CeO2 films
| Authors | |
|---|---|
| Year of publication | 2011 |
| Type | Article in Periodical |
| Magazine / Source | Russian Journal of Electrochemistry |
| MU Faculty or unit | |
| Citation | |
| Field | Plasma physics |
| Keywords | CeO2 ; Sm2O3 ; e-beam evaporation ; ionic beam assisted deposition ; impedance spectroscopy ; indentation technique ; electrical conductivity ; dielectric permittivity ; microhardness ; |
| Description | Electrical conductivity, dielectric permittivity and mechanical hardness of the polycrystalline CeO2 + xSm2O3 (x = 0, 10.9-15.9 mol %) films prepared by Electron Beam Physical Vapour Deposition (EB-PVD) and Ionic Beam Assisted Deposition, (IBAD), techniques were investigated in dependence on their structure and microstructure influenced by the deposition conditions, namely composition, deposition temperature and Ar+ ion bombardment. The electrical conductivity of doped ceria prepared without Ar+ ion bombardment and investigated by the impedance spectroscopy, IS, was found to be predominantly ionic one under the oxidizing atmosphere/low-temperature conditions and the higher amounts of Sm2O3 (>10 mol %) used. The bulk conductivity as a part of total measured conductivity was a subject of interest because the grain boundary conductivity was found to be 3 orders of magnitude lower than the corresponding bulk conductivity. Ar+ ion bombardment acted as a reducer (Ce4+ -> Ce3+) resulting in the development of electronic conductivity. Dielectric permittivity determined from the bulk parallel capacitance measured at room temperature and the frequency of 1 MHz, similarly as the mechanical hardness measured by indentation (classical Vickers and Depth Sensing Indentation-DSI) techniques were also found to be dependent on the deposition conditions. The approximative value of hardness for the investigated films deposited on the substrate was estimated using a simple phenomenological model described by the power function HV = HV0 + aPb and compared with the so-called apparent hardness (substrate + investigated film) determined by the classical Vickers formula. Results obtained are analyzed and discussed. |
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