Irreversible magnetization and upper critical field of YBa2Cu3O7 single crystals in high magnetic fields

Quasi-2D behaviour of HTSCs: the consequence of the small effective thickness of superconducting layers

“…This is valid, of course, only if d ξ 0 . Because in HTSCs ξ 0 ≈ 10-30 Å [32][33][34], a layer several angstroms thick would satisfy this requirement quite well.…”

Magnetization Relaxation and Resistive Behaviour of High-Tc Superconductors

“…In the flux-creep regime the drift velocity of flux-lines is given by the usual expression [14] UCT,B) kT (9) where v is a velocity prefactor related to the attempt frequency for flux-line hopping, j is the Yocal current density and Aj is the change in the energy of a flux-line associated with the Lorentz force acting on a vortex [15]. In the flux-flow regime the velocity of flux-lines is limited by a viscous drag, in which the simple Stephen-Bardeen [16] model, i9 given by (10) where P n is the normal state resistivity and B c2 (T) the upper critical field [17] Expression (12) has the correct limiting behavior for j ~ 0 and j ~ 00, if S exp[U(T,B)/kT) ~ B c2 (T)/BP n ). At low current densities the ereep-term dominates while at eurrent densities j ~ U(T,B)/A the sinh-term increases so rapidly that the flow-term becomes the dominant term in the denominator of Eq.…”