Giant suppression of flux-flow resistivity in heavy-ion irradiated ${\mathrm{Tl}}_2$${\mathrm{Ba}}_2$${\mathrm{Ca}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{10}$ films: Influence of linear defects on vortex transport

A large shift of the onset of flux-flow resistivity and the irreversibility line ${\mathit{H}}_{\mathrm{irr}}$(T) to higher temperatures is observed in ${\mathrm{Tl}}_2$ ${\mathrm{Ba}}_2$ ${\mathrm{Ca}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{10}$ films containing linear defects created by ${\mathrm{Ag}}^{+21\mathrm{}}$ ion irradiation. The ${\mathit{H}}_{\mathrm{irr}}$(T), which has a characteristic ssL shape in highly anisotropic Tl and Bi based cuprates, becomes more like that of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ in the presence of these defects. The ${\mathit{J}}_{\mathit{c}}$ at 77 K also shows a large increase as a result of flux localization at the defects. The transport data indicate that in the H-T plane above ${\mathit{H}}_{\mathrm{irr}}$(T) of the unirradiated material, an ensemble of unoccupied defects is required for effective pinning of each flux line in the system.