Origin of the irreversibility line in thin YBa 2Cu 3O 72d films with and without columnar defects
نویسندگان
چکیده
We report on measurements of the angular dependence of the irreversibility temperature T irr(u) in YBa2Cu3O72d thin films, defined by the onset of a third-harmonic signal and measured by a miniature Hall probe. From the functional form of T irr(u) we conclude that the origin of the irreversibility line in unirradiated films is a dynamic crossover from an unpinned to a pinned vortex liquid. In irradiated films the irreversibility temperature is determined by the trapping angle. @S0163-1829~96!01245-3#
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