ELECTRON-IRRADIATION EFFECTS IN YBA2CU3O6+X AND HGBA2CA2CU3O8+DELTA CRYSTALS

We have investigated the effects of electron irradiation on various si ngle crystals, i.e. YBa2Cu3O6+x (YBCO6+x) with x = 0.6, 0.8 and simila r to 1 and HgBa2Ca2Cu3O8+delta (Hg-1223). It appears that the decrease of the critical temperature (T-c) and the increase of the in-plane re sistivity under irradiation have the same origin in all samples, namel y defects created in the CuO2 planes. For YBCO, we found similarities between electron irradiation and Zn doping effects. Indeed, the decrea se rate of T-c as a function of the fluence of irradiation is roughly two times higher for underdoped compounds than for the optimally doped one.