Authors: Tayebeh Mousavi Chris Grovenor Susannah Speller
Publish Date: 2015/07/17
Volume: 50, Issue: 21, Pages: 6970-6978
Abstract
We have investigated the feasibility of RF sputtering for the deposition of superconducting Fe y Se1−x Te x Fe11 thin films on singlecrystalline MgO substrates Phase evolution and texture development as a function of processing conditions were studied and the optimum conditions for highquality films are reported The epitaxial growth of the pure Fe11 phase occurs in a temperature range of 300–320 °C with a critical film thickness of 50 nm Caxis alignment is obtained in almost all processing conditions while inplane alignment is shown to be strongly dependent on the substrate temperature and the film thickness When the substrate temperature exceeds 325 °C an interlayer is formed between films and substrates which precludes epitaxial growth Using sputtering with a single 3element target the deposited films tend to be enriched in Fe content and the excess Fe suppresses superconductivity but a sharp transition at 102 K is found for the films with an Fe/Se + Te ratio close to 1
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