AVS 54th International Symposium | |
Thin Film | Thursday Sessions |
Session TF-ThP |
Session: | Aspects of Thin Films Poster Session |
Presenter: | K. Smet, University Ghent, Belgium |
Authors: | K. Smet, University Ghent, Belgium R. De Gryse, University Ghent, Belgium |
Correspondent: | Click to Email |
In this work we propose a novel way of explaining the XRD-spectra of our rotatable dc-magnetron low pressure sputtered YBa2Cu3O7-δ and NdBa2Cu3O7-δ thin films. As is frequently the case at low pressure sputtering our films exhibit an expanded c-axis. This expansion is usually attributed to oxygen deficiency and/or cation-disorder in the Re-Ba2Cu3O7-δ structure. However under certain conditions (low pressure, Cu co-sputtering, lowering deposition temperature,...) the spectra of our films not only reveal an expanded c-axis but the (00n) peaks also tend to split up, whereby one peak has the theoretical c-axis value while the other shows an enlargement. This behaviour suggests the presence of two phases in our thin films. A closer look at XRD-spectra of some of our thin films suggest that a large c-axis expansion in Cu-poor conditions might be attributed to the presence of Y2Ba2O5. The conditions triggering the split as well as the possible presence of Y2Ba2O5, point to the importance of the energy and/or valence state of the Cu atoms during the deposition process. Therefore in this paper we explore a possible explanation for the peak splitting in the XRD-spectra of our thin films based not only on the abundance of the Cu atoms at the substrate but also on their energy or valence state.