Magnetic-field-induced finite-size effect in the nigh-temperature superconductor YBa2Cu3O(7-delta): a comparison with rotating superfluid 4He.
The effect of strong magnetic fields (11 T) on superconductivity in YBa2Cu3O(7-delta) is investigated using high-resolution thermal expansion. We show that the field-induced broadening of the superconducting transition is due to a finite-size effect resulting from the field-induced vortex-vortex length scale. The physics of this broadening has recently been elucidated for the closely related case of rotating superfluid 4He [Phys. Rev. B 60, 12 373 (1999)]]. Our results imply that the primary effect of magnetic fields of the order of 10 T is to destroy the phase coherence; the pairing, on the other hand, appears to be quite insensitive to these fields.
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Forschungszentrum Karlsruhe, Institut für Festkörperphysik, 76021 Karlsruhe, Germany.
Meingast
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Rykov
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Tajima
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