ac response of Hg-based superconductors: Surface barrier and bulk pinning contributions
نویسندگان
چکیده
A complete study of the ac response of Hg-based superconductors with 1, 2, and 3 Cu-O planes is presented. Under a dc field, the ac susceptibility xac(T) displays a double transition, which is argued to be of intrinsic nature. The systematic analysis of the evolution of xac ~fundamental and higher harmonics! as a function of the experimental parameters, and the comparison with resistance and dc magnetization measurements, suggest that the higher temperature transition is ascribed to magnetic irreversibility due to surface barriers; the lower temperature transition is associated to bulk pinning.
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