The effect of low-temperature electron irradiation on the transition temperature of YBa2Cu3O7−δ superconductors

Measurements of the complex susceptibility χ=χ′−iχ″ of electron-irradiated YBa2Cu3O7−δ show a strong influence of the electron irradiation dose, Φ·t on the transition temperatureT c . For irradiation doses of Φ·t=2.2·1019 e−/cm2 we find a damage rate of ΔT c /Δ(Φ·t)=−1.6·10−19 K/(e−/cm2). It is assumed that the decrease ofT c is mainly a bulk effect due to the production of atomic defects like vacancies and interstitials in the Cu−O−Cu chains and in the basal planes of the unit cells.