Substrate Effect on Thermal Stability of Superconductor Thin Films in the Peritectic Melting

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• 作者：Y. Y. Chen ; T. F. Fang ; S. B. Yan ; X. Yao ; B. W. Tao
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：May 31, 2012
• 年：2012
• 卷：116
• 期：21
• 页码：6187-6192
• 全文大小：290K
• 年卷期：v.116,no.21(May 31, 2012)
• ISSN：1520-5207

文摘

Systematic experiments were performed by in situ observation of the YBa₂Cu₃O_z (Y123 or YBCO) melting. Remarkably, the superheating phenomenon was identified to exist in all commonly used YBCO thin films, that is, films deposited on MgO, LaAlO₃ (LAO), and SrTiO₃ (STO) substrates, suggesting a universal superheating mode of the YBCO film. Distinctively, YBCO/LAO films were found to possess the highest level of superheating, over 100 K, mainly attributed to the lattice match effect of LAO substrate, that is, its superior lattice fit with Y123 delaying the Y123 dissolving and inferior lattice matching with Y₂BaCuO₅ (Y211) delaying the Y211 nucleation. Moreover, strong dependence of the thermal stability on the substrate material for Y123 films was also found to be associated with the substrate wettability by the liquid and the potential element doping from the substrate. Most importantly, the understanding of the superheating behavior is widely valid for more film/substrate constructions that have the same nature as the YBCO film/substrate.