Baumann, M; Wirth, G; Kötzler, J - In: Physica A: Statistical Mechanics and its Applications 266 (1999) 1, pp. 255-262
By high-resolution SQUID-magnetometry, we study the influence of columnar defects of field-equivalent density Bφ=1T on the flux creep in thin YBa2Cu3O7−δ films. At temperatures T∗(B,Bφ), the relaxation rates reveal a sharp crossover from a glassy dynamics to a faster algebraic flux creep...