140 MeV Si-ION irradiation induced T_c enhancement in YBCO thin films

摘要

On-line resistance measurement in a temperature range of 78 K to 124 K was performed on epitaxial thin films of YBCO irradiated with 140 MeV Si ions. The superconducting transition temperature (T_c), resistivity at 100 K (#rho# 100 k) and transition width (#DELTA#T_c) all show peak at a fluence of 1.5 * 10~(13) ions/cm~2. A crystallochemical analysis based on metastability induced charge and spin fluctuation due to irradiation induced oxygen disorder in the CuO chains explains the T_c enhancement in the low fluence regime.