https://doi.org/10.1140/epjb/e2004-00387-2
Flux dynamics, superconducting, and normal state properties of Gd(Ba2-xPrx)Cu3O7+δ
Magnet Research Laboratory (MRL), Department of Physics, Sharif University of Technology, P.O. Box 11365-9161, Tehran, Iran
Corresponding author: a akhavan@sharif.edu
Received:
27
November
2003
Revised:
4
July
2004
Published online:
23
December
2004
Gd(Ba2-xPrx)Cu3O7+δ single phase
polycrystalline samples with were investigated for
structural, electronic and flux dynamics properties. Two-dimensional
variable range hopping (VRH) is the dominant conduction mechanism in the
normal state of the system. Pr doping strongly localizes the carriers in
normal state, and finally causes the suppression of superconductivity. The
effect of Pr substitution in 123 structure of HTSC at R or Ba sites is to
increase the pseudogap temperature Ts, although, Pr at Ba sites has a
stronger effect on the increase of Ts and suppression of
superconductivity. The magnetoresistance of the samples have been studied
within thermally activated flux creep and the Ambegaokar and Halperin phase
slip models. The derived critical current density,
,
,
and superconducting coherence length
show that the Pr doping, like
weak links, decreases the vortex flux pinning energy. Our results imply that
understanding the real suppression mechanism of superconductivity by Pr
doping in HTSC is connected crucially to the exact position of Pr in the
structure.
PACS: 74.72.Bk – Y-based cuprates / 74.62.Dh – Effects of crystal defects, doping and substitution / 74.62.Bf – Effects of material synthesis, crystal structure, and chemical composition / 74.25.Fy – Transport properties (electric and thermal conductivity, thermoelectric effects, etc.) / 74.25.Op – Mixed states, critical fields, and surface sheaths
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004