Strain Effects on the Crystal Growth and Superconducting Properties of Epitaxial Niobium Ultrathin Films
| Autor: | K. C. Wong, C. E. Reece, W. M. Roach, A. D. Batchelor, Douglas Beringer, J. R. Skuza, Cesar Clavero, Rosa A. Lukaszew |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Condensed matter physics Niobium chemistry.chemical_element Crystal growth General Chemistry Condensed Matter Physics Epitaxy Microstructure Condensed Matter::Materials Science Crystallography Lattice constant chemistry Sputtering Condensed Matter::Superconductivity Sapphire General Materials Science Thin film |
| Zdroj: | Crystal Growth & Design. 12:2588-2593 |
| ISSN: | 1528-7505 1528-7483 |
| Popis: | Superconducting ultrathin films grown epitaxially onto crystalline substrates exhibit strained epitaxial growth due to lattice mismatch, which can have a significant effect on their superconducting properties. We present a complete correlation of the surface morphology, crystal growth, strain, microstructure, and superconducting properties in single-crystal Nb(110) thin films sputter deposited on a-plane sapphire substrates. Notably, we observe that the lattice mismatch between Nb and sapphire induces the formation of a hexagonal surface structure during the first three atomic layers. This is followed by a strained bcc Nb(110) phase whose in-plane lattice parameter progressively relaxes to bulk value. Similar lattice relaxation was also observed in the direction perpendicular to the interface using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Significant perpendicular strain in films up to 30 nm thick was found to ultimately affect the superconducting properties of the Nb thin films... |
| Databáze: | OpenAIRE |
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