Connection of residual losses of a microwave energy in superconducting state of YBa_2Cu_3O_(7-δ) films on sapphire substrates with their resistance in a normal state

摘要

In the work, the results of measurements of temperature dependence of the surface resistance R_S(T) of the YBa_2Cu_3O_(7-δ) epitaxial films deposited on sapphire substrates have been presented. The films were obtained using the method of impulse laser deposition. The measurements of surface impedance R_S(T) have been carried out at a frequency of 135 GHz. It is shown that R_S(T) agrees with existing model, considering heterogeneity in the YBa_2Cu_3O_(7-δ) epitaxial films as the normal spherical domains. Analysis has been carried out for the set of specimens which were obtained at different technological regimes and have different critical parameters and geometry.