About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Paper
Magnetic relaxation in an isotropic extreme type-II superconductor
Abstract
The time dependence of the zero-field-cooled and thermoremanent magnetization of the isotropic extreme type-II superconductor PbMo6S8 has been measured at temperatures 0.7T/Tc0.95 and for fields 1H300 G. The results show that the time dependence of the decay can be divided into three different field regimes: (1) A low-field regime with a closely logarithmic decay and a well-established critical state. The relaxation rate [M/ ln(t)] increases as H5 for the zero-field-cooled magnetization and as H2.4 for the thermoremanent magnetization. The reduction in magnetization over 5 decades in time (0.3"3×104 s) is, at most, a few percent. (2) A crossover-field regime with a change from a logarithmic to a nonlogarithmic decay. (3) A high-field regime where the time dependence of the decay is well described by the expression M[ln(t/0)]-. The reduction in magnetization in the crossover- and high-field regimes is as large as 25"30 % in the measured time interval. The results in the high-field regime are interpreted within the theory of collective flux creep. Comparisons are made with the magnetic relaxation found in anisotropic high-Tc superconductors. © 1991 The American Physical Society.