https://doi.org/10.1007/s100510050936
Nonlinear ac response of the vortex system in the cubic (K, Ba)BiO3 superconductor
1
Laboratoire d'Études des Propriétés Électroniques des
Solides, Centre National de la Recherche
Scientifique, B.P. 166,
38042 Grenoble
Cedex 9, France
2
Departemento de Fisica, CINVESTAV-IPN, Apdo, Postal 14-740,
Mexico D.F. 07300, Mexico
Corresponding author: a klein@lepes.polycnrs-gre.fr
Received:
17
March
1999
Published online: 15 September 1999
We present ac susceptibility measurements performed
on 
single crystals with different geometries: thick films, bars and hollow
cylinders. We show that the hac dependence of the real (
) and
imaginary (
) parts of the ac susceptibility is in very good agreement
with Brandt's numerical calculations (Phys. Rev. B 58, 6523 (1998)) in the
modified Bean critical state. Creep effects (at 
) are
investigated
by studying the frequency dependence of the current density deduced from the
temperature scans of the ac susceptibility over a large frequency range (
). The relaxation rate
is
temperature independent and very similar to
the one usually obtained in high
Tc cuprates.
PACS: 74.60.Ge – Flux pinning, flux creep, and flux-line lattice dynamics / 74.60.Ec – Mixed state, critical fields, and surface sheath / 74.25.Nf – Response to electromagnetic fields (nuclear magnetic resonance, surface impedance, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
