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Effect of varying material anisotropy on critical current anisotropy in vicinal YBa2Cu3O7-delta thin films


Type

Article

Change log

Authors

Durrell, JH 
Evetts, JE 
Rossler, R 
Delamare, MP 
Pedarnig, JD 

Abstract

The high Tc cuprate superconductors are noted for their anisotropic layered structure, certain of these materials indeed tend toward the limit of a Lawrence-Doniach superconductor. However, YBa2Cu3O7−δ has a smaller anisotropy than would be expected from its interlayer spacing. This is due to the cuprate chains in the structure. To investigate the influence of the chain oxygen on transport properties critical current versus applied field angle measurements were performed on fully oxygenated and de-oxygenated YBa2Cu3O7−δ thin films and optimally oxygenated Y0.75Ca0.2Ba2Cu3O7−δ thin films. The films were grown on 10 mis-cut SrTiO3 substrates to enable the intrinsic vortex channelling effect to be observed. The form of the vortex channelling minimum observed in field angle dependent critical current studies on the films was seen to depend on film oxygenation. The vortex channelling effect is dependent on a angular dependent cross-over to a string-pancake flux line lattice. The results obtained appear to be consistent with the prediction of Blatter et al. [Rev. Mod. Phys., 66 (4): 1125 (1994)] that increased superconducting anisotropy leads to the kinked string-pancake lattice existing over a smaller angular range.

Description

Keywords

OXYGEN STOICHIOMETRY, SUPERCONDUCTIVITY, VORTICES, CRYSTAL, FIELD

Journal Title

Applied Physics Letters

Conference Name

Journal ISSN

0003-6951
1077-3118

Volume Title

83

Publisher

American Institute of Physics
Sponsorship
EPSRC