Irradiation hardening of Mg-doped TlBa2(Ca2−yMgy)Cu3O10−δ superconductors

• Decrease in Tc (0) and increase in residual resistivity were observed after ions irradiation.
• Significant broadening in transition widths was observed after ions irradiation.
• Ions irradiation hardening was observed in Mg-doped samples.
• Optimum defects density and size of defects are very important for efficient pinning centers.

Superconducting Mg-doped TlBa2(Ca2−yMgy)Cu3O10−δ (y=0, 0.5, 1.0, 1.5) samples were irradiated with gold (Au+4) ions. The zero resistivity critical temperature {Tc (0)} was decreased and residual resistivity was increased after irradiation. The irradiation-induced suppression of Tc (0) can be related with several factors, such as reduction of superconducting volume fraction caused by damaging and deterioration of samples quality after Au+4 ions irradiation. A pronounced fishtail was observed in all the samples with the applied magnetic field and all these features qualitatively agreed with the predictions of the order–disorder theory of vortex matter. The significant broadening in transition widths as function of external applied field was observed after ions irradiation. The activation energy was increased with the increasing Mg contents and Au+4 ions irradiation. But the activation energy of irradiated samples remained higher as compared to un-irradiated samples for all the values of external applied magnetic field. Almost similar decreasing trend in activation energy was observed with increasing magnitude of external applied magnetic field in all the samples. The ions irradiation hardening was observed in Mg-doped TlBa2(Ca2−yMgy)Cu3O10−δ samples.