We report on measurements of the angular dependence of the irreversibility temperature (Formula presented) in (Formula presented) thin films, defined by the onset of a third-harmonic signal and measured by a miniature Hall probe. From the functional form of (Formula presented) 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.
|Number of pages
|Physical Review B - Condensed Matter and Materials Physics
|Published - 1996