Vortex state microwave resistivity in Tl-2212 thin films

• Published in: Journal of superconductivity and novel magnetism Vol. 20; no. 1; pp. 43 - 49
• Main Authors: POMPER, N, SARTI, S, MARCON, R, SCHNEIDEWIND, H, SILVA, E
• Format: Conference Proceeding Journal Article
• Language: English
• Published: New York, NY Springer 01.01.2007
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Properties of type I and type II superconductors; Response to electromagnetic fields (nuclear magnetic resonance, surface impedance, etc.); Superconductivity; Vortex lattices ,flux pinning, flux creep; Frequency dependence; Flux line; Electrical conductivity; Low field; Thin films; Irreversible processes; Calcium oxides; Thallium oxides; Superconducting films; Monocrystals; Microwave conductivity; Barium oxides; Vortices; microwave response; Dissipation; Scaling laws; High-Tc superconductors; Vortex motion; Tl:2212; Copper oxides
• ISSN: 1557-1939; 1557-1947
• DOI: 10.1007/s10948-006-0187-2

We present measurements of the field induced changes in the 47 GHz complex resistivity, Deltarho~(H, T), in Tl2Ba2CaCu2O8+x (TBCCO) thin films with T c {asymptotically equal to} 105 K, prepared on CeO2 buffered sapphire substrates. At low fields (mu0 H < 10 mT) a very small irreversible feature is present, suggesting a little role of intergranular phenomena. Above that level Deltarho~(H, T exhibits a superlinear dependence with the field, as opposed to the expected (at high frequencies) quasilinear behaviour. We observe a crossover between predominantly imaginary to predominantly real (dissipative) response with increasing temperature and/or field. In addition, we find the clear scaling property Deltarho~(H, T = Deltarho~[H/H (T)], where the scaling field H (T) maps closely the melting field measured in single crystals. We discuss our microwave results in terms of loss of flux lines rigidity.