Microwave properties of YBa sub(2)Cu sub(3)O sub(7- delta ) thin films grown on MgO or Al sub(2)O sub(3) substrates

• Published in: Physica. C, Superconductivity Vol. 271; no. 1-2; pp. 67 - 78
• Main Authors: Chambonnet, D, Mehri, F, Degoy, S, Lederer, P, Belouet, C, Fages, C, Keller, D, Carru, J C, Correra, L
• Format: Journal Article
• Language: English
• Published: 01.01.1996
• ISSN: 0921-4534

The conductivity sigma super(*) identical with sigma sub(1) + j sigma sub(2) of YBCO films grown by pulsed laser assisted deposition on (100) MgO and (1 1 02) Al sub(2)O sub(3) substrates was measured at 22 GHz using a microwave transmission method. A peak close to the transition temperature was observed in the sigma sub(1)(T) curves. This peak is ascribed to a specific behavior of the granular superconducting material with a small spread (a few degrees) in the critical temperature. This granularity is also responsible for the observed large value of the penetration depth.