Effect of light ion irradiation on the flux dynamics of YBa2Cu3O7-delta thin films

Thin films of 123 cuprates (YBa2Cu3O7) grown by DC sputtering are irradiate d with light ion (He+) at 80 keV and with doses in the range 10(14) -10(15) cm(-2). The point disorder defects, due to light ion irradiation, cause a systematic decrease of the critical temperature. The effect of light ion ir radiation on the vortex phase behavior is explored by critical currents fro m transport and magnetization loops (solid vortex phase) and resistivity (l iquid state) in perpendicular fields. Although point disorder does not sign ificantly affect dissipation in the solid state, the dissipation in the liq uid is governed by plastic deformation of vortices favored by point disorde r pinning.