The effect of electron irradiation upon the stability of defects during thermal cycling was studied. It was shown that an ab-plane resistivity increase in both compounds was due to a decrease, in the mean free path, that was caused by defects which had been created in the CuO2 planes. The defects began to anneal out at temperatures above 100K. At 300K, only 50% of the low-temperature defect concentration remained.

F.Rullier-Albenque, A.Legris, H.Berger, L.Forro: Physica C, 1995, 254[1-2], 88-92