Critical-state model with a secondary high-field peak in J{sub c}(B)
- Department of Physics, University of Oslo, P.O. Box 1048, Blindern, 0316 Oslo 3 (Norway)
A critical-state model capable of describing the experimentally observed secondary or fishtail peak in magnetization data for bulk high-T{sub c} superconductors is introduced. As suggested by a recent understanding of the fishtail effect, the field dependence of the critical current density is taken as a sum of two terms; one giving rise to a low-field magnetization peak and another being responsible for the fishtail peak. The model, which extends the Kim model by adding a Lorentzian term in J{sub c}(B), allows analytical treatment. Expressions for internal flux-density profiles as well as the various branches of the magnetization loop are presented. It is shown that measured magnetization loops of NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} samples showing a very pronounced fishtail peak are well fitted by this model. Using our procedure, J{sub c}(B) can be determined without invoking the Bean model (with a constant J{sub c}), and thus avoiding an inconsistency in the analysis. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 544924
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 17 Vol. 56; ISSN 0163-1829; ISSN PRBMDO
- Country of Publication:
- United States
- Language:
- English
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