Excess conductivity analysis of heavy ions irradiated TlBa2(Ca2−yMgy)Cu3O10−δ superconductor

The excess conductivity analysis of resistivity versus temperature data of TlBa2(Ca2−yMgy)Cu3O10−δ (y=0.5, 1.0, 1.5) superconductor samples have been performed in the light of Aslamasov-Larkin and Lawrence-Doniach theories before and after irradiation with a beam of gold (Au4+) ions of energy 20 MeV having a fluence of 1×1015 ions/cm2. The microscopic parameters such as zero temperature coherence length {ξc(0)}, inter-plane coupling constant (α), and Fermi velocity (VF) have been calculated from the ln-ln plot of excess conductivity (Δσ) versus reduced temperature (ε) using the Lawrence and Doniach model. The cross-over temperatures separating different fluctuation regions in the ln-ln plot are also determined. It is observed from the excess conductivity analysis that all the microscopic parameters have been decreased after the irradiations. Whereas, calculations have shown that critical magnetic fields (Bc) and critical current density (Jc) are increased after the ion irradiation, which, confirms the validity of the results because Bc and Jc are increased by the formation of artificial pinning centers after bombardment of energetic heavy ion beam.