Critical currents and magnetic relaxation of epitaxial YBa2Cu3O7 - δ films

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Critical currents and magnetic relaxation of epitaxial YBa2Cu3O7 - δ films

Journal Article (1989)

Author(s)

R. Griessen (Vrije Universiteit Amsterdam)

C. F.J. Flipse (Vrije Universiteit Amsterdam)

C. W. Hagen (Vrije Universiteit Amsterdam)

J. Lensink (Vrije Universiteit Amsterdam)

B. Dam (Philips Research Laboratories)

G. M. Stollman (Philips Research Laboratories)

Affiliation

External organisation

DOI related publication

https://doi.org/10.1016/0022-5088(89)90294-4 Final published version

To reference this document use

https://resolver.tudelft.nl/uuid:3290715d-5254-4259-8bc1-a85b910a1424

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Publication Year

1989

Language

English

Affiliation

External organisation

Journal title

Journal of The Less-Common Metals

Volume number

151

Pages (from-to)

39-48

Downloads counter

46

Abstract

Critical currents of YBa2Cu3O7 - δ epitaxial films, obtained by co-evaporation of yttrium, copper and BaF2 in an ultrahigh vacuum system, were measured using resistometric and magnetic torque methods. Typical values of jc $ ̌2 × 1011 A m-2 at 4.2 K and 4 × 1010 A m-2 at 77 K were found. In spite of their good quality these films exhibited large magnetic relaxation even at 4.2 K. Using the results of Monte-Carlo simulations of thermally activated flux motion for the analysis of the relaxation data typical values of 25 ± 3 meV were found for the activation energy U of flux motion at 4.2 K. It is shown that the occurrence of highjc values and small activation energies is not inconsistent in high Tc superconductors because of their short coherence lengths.