About normal clusters formation in high-Tc superconducting YBa2Cu3O7-δ films on sapphire substrates

Measurement data of the surface resistance R_s(T) temperature dependence of YBa₂Cu₃O_7-δ epitaxial films on sapphire substrates are reported. The films were prepared by an impulse laser ablation technique. Surface impedance measurement was made in the 65 GHz frequency range. We shown that Rs(T) is in accordance with the epitaxial film considering the existence of spatial inhomogeneities as normal spherical domains. The analysis of YBa ₂Cu₃O_7-δ film contamination was made by a laser mass-spectrometry technique. It was shown that the normal spherical domains of the YBa₂Cu₃O_7-δ films include oxidizer copper compounds filling cluster voids and film edges. The measurement was made for YBa₂Cu₃O_7-δ films over the course of five-years