The role of the substrate surface morphology in enhancing the MgB sub(2) superconducting temperature

• Published in: Journal of materials science Vol. 49; no. 11; pp. 4108 - 4114
• Main Authors: Orgiani, Pasquale, Ciancio, Regina, Wolak, Matthaeus A, Xi, Xiao Xing
• Format: Journal Article
• Language: English
• Published: 01-06-2014
• Subjects: Borides; Critical temperature; Magnesium compounds; Morphology; Silicon carbide; Silicon substrates; Superconductivity; Thin films
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-014-8104-8

We hereby report on the role of the surface morphology of various substrates in the enhancement of the superconducting critical temperature of MgB sub(2). MgB sub(2) thin layers were grown by hybrid physical-chemical vapour deposition on silicon carbide SiC substrates/fibers and several other substrates, characterized by diverse surface morphologies. By investigating the structural, morphological and transport properties of MgB sub(2) thin layers, the presented data show that the superconducting critical temperature T sub(c) exceeds the bulk value only when the MgB sub(2) films are grown on atomically flat (0001) SiC single crystals and on MgB sub(2) bottom layers. These results further confirm the interpretation of the coalescence-driven tensile strain mechanism behind the enhancement of superconducting properties in MgB sub(2) thin films.