Low Temperature Physics: 31, 254 (2005); https://doi.org/10.1063/1.1884427 (9 pages)
Fizika Nizkikh Temperatur: Volume 31, Number 3-4 (March 2005), p. 339-349    ( to contents , go back )

Microwave surface impedance of high-temperature superconducting YBa2Cu3O7-d films in magnetic field

V.M. Pan, D.A. Luzhbin, O.A. Kalenyuk, A.L. Kasatkin, V.A. Komashko

Institute of Metal Physics, National Academy of Sciences of Ukraine 36 Vernadskogo Ave., Kiev, 03142, Ukraine
E-mail: pan@imp.kiev.ua

A.V. Velichko, M.J. Lancaster

University of Birmingham, School of Electronic, Electrical and Computer Engineering, B15 2TT, UK
pos Анотація:

Received August 3, 2005

Abstract

The temperature, ac- and dc-field dependences of microwave surface impedance in superconducting perfect single-crystalline YBa2Cu3O7–d films obtained by magnetron deposition on sapphire substrates buffered by CeO2, were measured by the coplanar resonator technique at frequency 5,25 GHz in the presence of applied weak dc magnetic field 0 < B < 12 mT. The microwave measurements were performed within a temperature range 13 < T < 80 K allowed us to obtain temperature and dc magnetic field dependences of surface resistance and penetration depth and to distinguish the contribution of oscillating Abrikosov vortices to the microwave response of the film. Besides, two kinds of experiments were performed in applied dc magnetic field B namely: field cooled and zero field cooled measurements. The experiments revealed a significant difference between microwave vortex responses for FC and ZFC regimes. The linear vortex response is discussed on the basis of Coffey–Clem`s and Brandt`s phenomenological theories of ac vortex response, the nonlinear one — on the basis of the critical-state theory.

PACS:
74.25.Nf - Response to electromagnetic fields (nuclear magnetic resonance, surface impedance, etc.)
74.25.Qt - Vortex lattices, flux pinning, flux creep
74.72.Bk - Y-based cuprates

Download 214916 byte View Contents