Melting and transverse depinning of driven vortex lattices in the periodic pinning of Josephson junction arrays

Abstract

We study the nonequilibrium dynamical regimes of a moving vortex lattice in the periodic pinning of a Josephson junction array ͑JJA͒ for finite temperatures in the case of a fractional or submatching field. We obtain a phase diagram for the current driven JJA as a function of the driving current I and temperature T. We find that when the vortex lattice is driven by a current, the depinning transition at T p (I) and the melting transition at T M (I) become separated even for a field for which they coincide in equilibrium. We also distinguish between the depinning of the vortex lattice in the direction of the current drive, and the transverse depinning in the direction perpendicular to the drive. The transverse depinning corresponds to the onset of transverse resistance in a moving vortex lattice at a given temperature T tr . For driving currents above the critical current we find that the moving vortex lattice has first a transverse depinning transition at low T, and later a melting transition at a higher temperature T M ϾT tr .

Superconducting vortex pinning with artificial magnetic nanostructures

“…Theoretical work on different systems with square pinning potentials [61,[144][145][146] has shown the possibility of guided vortex motion along the principal axes and diagonals of the arrays. This effect has been observed experimentally in a limited angular range for superconducting films with square arrays of antidotes [147].…”

Vortex Motion Rectification in Josephson Junction Arrays with a Ratchet Potential

“…The fact that this feature is observed for high densities can be taken as an indication that vortex-vortex interactions overcome the geometrical potential landscape and effectively change the shape and asymmetry of the ratchet potential. A change in the structure of the vortex system occurs on dynamical phases [21], changing the vortexvortex interactions. As a result a sign reversal of the rectified motion can arise at high vortex velocities.…”

Peak effect and dynamic melting transitions of driven vortex system in weakly disordered Josephson junction arrays

“…31 To remedy this problem, one can fix one of the phases, which amounts to deleting one row and one column from M. The N coupled equations of motion given in Eq. ͑3͒ could be rewritten by inverting the matrix M and expressing d⌽ / dt in terms of C. However, M is not invertible as it stands.…”

“…[28][29][30][31][32][33][34][35][36] It is of great interest to study the solid-solid transition and the nature of the pinning for disordered JJAs. [28][29][30][31][32][33][34][35][36] It is of great interest to study the solid-solid transition and the nature of the pinning for disordered JJAs.…”