| 1. |
- Andersson, Magnus, et al.
(författare)
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H-T PHASE-DIAGRAM OF DYBA2CU3O7-DELTA(Y0.45PR0.55)BA2CU3O7-DELTA MULTILAYERS IN THE MIXED-STATE
- 1994
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Ingår i: Physica. C, Superconductivity. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 235, s. 2617-2618
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Tidskriftsartikel (refereegranskat)abstract
- From measurements of I-V characteristics of DyBa2Cu3O7-delta/(Y0.45Pr0.55)Ba2Cu3O7.delta multilayers, we have experimentally determined the characteristic temperature separating the vortex liquid from the vortex solid. We suggest that the cross-over temperature is determined by the anisotropy given by the artificially layered structure of these multilayers and that the studied system can be used as a test system for vortex dynamics.
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| 2. |
- Andersson, Magnus, et al.
(författare)
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Vortex solid-to-liquid transition in DyBa2Cu3O7-delta/(Y0.45Pr0.55)Ba2Cu3O7-delta multilayers
- 1996
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 54:1, s. 675-681
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Tidskriftsartikel (refereegranskat)abstract
- Current-voltage (I-V) characteristics of a coupled multilayer system consisting of thin (24 Angstrom) superconducting layers of DyBa2Cu3O7-delta each separated by 96 Angstrom of (Y0.45Pr0.55)Ba2Cu3O7-delta have been studied in the mixed state. Analyses of vortex glass scaling and signs of the clean system melting transition in the dynamics of our multilayers both suggest that the vortex system is close to three-dimensional for magnetic fields up to several T. Therefore, the theoretically predicted crossover when in-plane vortex correlations become more important than out-of-plane vortex correlations (occurring at a few tenths of a T in our multilayers) does not correspond to a complete decoupling of the superconducting layers in these materials.
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| 3. |
- Fabrega, Lourdes, et al.
(författare)
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Vortex dynamics and vortex phase diagram in artificial oxide superlattices
- 1996
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Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 222:4, s. 379-384
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Obara, Haruhiko, et al.
(författare)
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Critical current properties of DyBa2Cu3O7/(Y1−xPrx)Ba2Cu3O7 multilayers
- 1994
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Ingår i: Physica. C, Superconductivity. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 235-240:PART 5, s. 2997-2998
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Tidskriftsartikel (refereegranskat)abstract
- Transport critical currents of DyBa2Cu3O7/(Y1−xPrx)Ba2Cu3O7 (DyBCO/YPrBCO) multilayers have been measured. Using careful meausurements of the temperature and magnetic field dependence of critical current density Jc of the multilayers, we observed two distinct regions in the solid vortex state. From these experimental results, we discuss the dimensionality, the vortex states, and the vortex pinning in the multilayers.
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| 5. |
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| 6. |
- Obara, Haruhiko, et al.
(författare)
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Vortex system in coupled DyBa2Cu3O7-delta(Y0.45Pr0.55)Ba2Cu3O7-delta heterostructures
- 1996
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Ingår i: Czechoslovak Journal of Physics. - 0011-4626 .- 1572-9486. ; 46:SUPPL. 3, s. 1565-1566
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Tidskriftsartikel (refereegranskat)abstract
- Transport measurements have been used to determine the vortex phase diagram (H parallel to c) of coupled heterostructures made of superconducting ultra-thin DyBa2Cu3O7-delta layers separated by semiconducting (Y0.45Pr0.55)Ba2Cu3O7-delta layers. These structures have an intermediate anisotropy between those of YBa2Cu3O7-delta and Bi2Sr2CaCu2O8+d. The solid-to-liquid transition and the flux dynamics have been investigated as a function of the total sample thickness d. Analyses of the parameters describing the thermally activated dissipation in the solid and liquid phases reveal a field induced crossover characterized by two fields, H-on(T) and H*>H-on. We discuss the meaning of these features and their relationship with results in bulk high temperature superconductors.
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