Effect of light ion irradiation on the flux dynamics of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films

Thin films of 123 cuprates (YBa/sub 2/Cu/sub 3/O/sub 7/) grown by DC sputtering are irradiated with light ion (He/sup +/) at 80 keV and with doses in the range 10/sup 14/-10/sup 15/ cm/sup -2/. The point disorder defects, due to light ion irradiation, cause a systematic decrease of the critical temperature. The effect of light ion irradiation on the vortex phase behavior is explored by critical currents from transport and magnetization loops (solid vortex phase) and resistivity (liquid state) in perpendicular fields. Although point disorder does not significantly affect dissipation in the solid state, the dissipation in the liquid is governed by plastic deformation of vortices favored by point disorder pinning.