Direct observation of tilted vortex structures induced by twin boundaries in YBa{sub 2}Cu{sub 3}O{sub y} single crystals
- Centre for High Temperature Superconductivity, Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)
- Forschungszentrum Karlsruhe, Institut fuer Technische Physik, D-76021 Karlsruhe (Germany)
In twinned YBa{sub 2}Cu{sub 3}O{sub y} single crystals we have observed that as the magnetic field {bold H} is tilted away from the c axis, a nearly {ital reversible} ab-plane magnetic moment m{sub ab} is generated that has a sharp maximum as a function of the tilt angle {var_phi}; this moment is absent from detwinned samples. Thus the measured direction of the vortices deviates from that of the applied field, reflecting their attraction to the twin boundaries (TB{close_quote}s). For a crystal with a single dominant direction of TB{close_quote}s, the size of m{sub ab} at low fields is consistent with ideal shielding of the ab-plane field component H{sub ab}, as expected for the vortex state that is fully locked to the TB{close_quote}s. The maximum in m{sub ab} at a fixed temperature occurs at a value of H{sub ab} that is nearly independent of {var_phi}; we identify this as the locking field H{sub L}. The trapping angle {var_phi}{sub T}, above which the kinked-vortex state vanishes, is apparent in the data too. The qualitative features of these results agree with current understanding of the vortex-TB interaction, but there are several quantitative discrepancies. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 528113
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 6 Vol. 56; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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