Relaxation and anomalous T- and H-dependence of the μ coefficient in superconductors
Laboratoire d'Etudes des Propriétés Electroniques des
Centre National de la Recherche Scientifique, BP. 166, 38042 Grenoble
Cedex 9, France
Accepted: 6 February 1998
Ac shielding and classical dc relaxation experiments have been used to study the flux creep phenomena in the cubic superconductor (). The relaxation rate is found to be constant () at low temperature and magnetic field and increases sharply as the vortex-glass transition line is approached. This behavior can be attributed to an anomalous decrease of the μ exponent () close to . In this regime, the temperature dependence of the apparent critical current J is then directly related to as . A similar analysis can be made on the J(B) data recently published by Abulafia et al. (Phys. Rev. Lett., 77 (1996) 1597) on single crystals.
PACS: 74.60.Ge – Flux pinning, flux creep, and flux-line lattice dynamics / 74.25.Ha – Magnetic properties
© EDP Sciences, 1998