Vortex dynamics and vortex phase diagram in artificial oxide superlattices

• DyBa2Cu3O7/(Y1-xPrx)Ba2Cu3O7 multilayers are model materials to study the nature of the vortex system in high-temperature superconductors and its dynamics. Indeed, by changing in such structures the thickness of the superconducting and the alloy layers, and the composition of the alloy, we can control at wish the critical temperature, the anisotropy and the pinning strength. Additionally, finite thickness effects may be studied. We review here our results on the study of the flux motion and phase diagram in coupled multilayers, displaying an intermediate anisotropy between those of YBa2Cu3 O-7 and Bi2Sr2CaCu2O8. Transport measurements with an applied field H/c allow to identify the solid and liquid phases in the mixed state, and reveal the presence of a field-induced crossover in the thermally activated dynamics of both phases, which lead us to draw a possible mixed state phase diagram for these artificial superconductors and correlate it to the existing results for other HTS.

Subject headings

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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