Experimental observation of $s$-component of superconducting pairing in thin disordered HTSC films based on YBCO

The original research results for thin disordered HTSC films based on YBCO are presented in this article. Several experiments have been carried out to confirm a theoretical prediction that the $s$-phase of superconducting pairing in disordered $d$-type superconductors can occur with a gradual decrease in the mean free path. The YBa$_{2}$Cu$_{3}$O$_{7-x}$ films were used as samples which possess a $d$-type of superconducting state that was experimentally confirmed. A gradual decrease in the mean free path was achieved by both thermal annealing and ion irradiation. The experiments included measurements of temperature dependence of the London penetration depth $\lambda$ and resistive studies.