A positron lifetime study on Y1−xPrxBa2Cu3O7−δ

Abstract The temperature dependence of the positron lifetime was measured in the range from 80 to 400 K for Y 1− x Pr x Ba 2 Cu 3 O 7− δ ( x = 0, 0.1, 0.3, 0.5, 0.7 and 1.0). The mean lifetime showed a clear temperature dependence for YBa 2 Cu 3 O 7− δ . As Pr is doped, the temperature dependence becomes weaker systematically. There is no temperature dependence of the mean lifetime for PrBa 2 Cu 3 O 7−δ . Two components can be extracted for the samples with x = 0, 0.1, 0.3 and 0.5 at lower temperatures. The long-lived lifetime is 188 ps and does not depend on either the Pr concentration or the temperature. The bulk lifetime of Y 1− x Pr x Ba 2 Cu 3 O 7− δ is 164 ps, regardless of the Pr concentration. Positron trapping effect is also discussed.