T-C ENHANCEMENT BY LOW-ENERGY-ELECTRON IRRADIATION AND THE INFLUENCE OF CHAIN DISORDER ON RESISTIVITY AND HALL-COEFFICIENT IN YBA2CU3O7 THIN-FILMS

The effect of electron irradiation with incident energy (E less than o r equal to 40 keV) lower than the threshold for displacement of in-pla ne atoms on T-c, resistivity and Hall coefficient has been studied on fully oxygenated YBa2Cu3O7-delta thin films. In contrast to the known T-c suppression at high-energy particle irradiation, an increase in T- c has been found as well as a factor of two increase in both the T-lin ear resistivity slope and the Hall coefficient as a function of radiat ion fluence. It has been shown that the changes observed in transport properties can be explained as being caused by disruption of the condu ctivity of CuO chains by radiation-induced chain oxygen defects.