Flux pinning properties of (Hg,A)(Ba,Sr)(2)Can-1CunO2n+2+delta (A = Re, Pb; n=1, ...,6) single crystals

Single crystals of mercury-based cuprate superconductors were grown under h igh pressure. In some crystals, Hg was partially substituted by Re or Pb an d Ba by Sr. With Re substitution, it was possible to obtain crystals with u p to six CuO2-layers. The flux pinning properties of the crystals were meas ured by SQUID magnetometry, and their irreversibility lines were compared. In lower magnetic fields and at higher temperatures, the flux pinning has a rather 3D character, whereas in higher magnetic fields and at lower temper atures, pinning is rather 2D. From the 2D/3D crossover field, the effective mass anisotropy could be estimated. (C) 2000 Published by Elsevier Science B.V. All rights reserved.