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Title: Anisotropy of magnetic vortex pinning in high- T sub c superconductors (invited) (abstract)

Journal Article · · Journal of Applied Physics; (United States)
DOI:https://doi.org/10.1063/1.349991· OSTI ID:5191702
 [1]
  1. IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, New York (USA)

There is no consensus as to the nature of the irreversibility line'' or the dynamic depinning transition boundary in {ital H}-{ital T} plane. The angle-resolved ac {chi} measurements allow us to probe the anisotropy of this boundary. We review remarkable new observations in single crystals of YBaCuO: one is the splitting of the loss peak in the out-of-phase ac susceptibility as a function of tilt angle between magnetic field and crystal axis, suggesting that vortices conform to the layered structure to form a modulated staircase'' shape. Another is the observation of a new {ital irreversibility} {ital collapse} transition in {ital H}-{ital T} plane at low fields near {ital T}{sub {ital c}}. The new regime may indicate a separate boundary in the magnetic phase diagram, below which the pinning barriers are thermally renormalized so that pinning is significantly reduced or negligible. We discuss these observations in the context of intrinsic pinning and collective effects.

OSTI ID:
5191702
Journal Information:
Journal of Applied Physics; (United States), Vol. 70:10; ISSN 0021-8979
Country of Publication:
United States
Language:
English