Dynamic transition in driven vortices across the peak effect in superconductors

Abstract

We study the zero-temperature dynamic transition from the disordered flow to an ordered flow state in driven vortices in type-II superconductors. The transition current Ip is marked by a sharp kink in the V (I) characteristic with a concomitant large increase in the defect concentration. On increasing magnetic field B, the Ip(B) follows the behaviour of the critical current Ic(B). Specifically, in the peak effect regime Ip(B) increases rapidly along with Ic. We also discuss the effect of varying disorder strength on Ip.

Structure and orientation of the moving vortex lattice in clean type-II superconductors

“…When the flux flow velocity increases beyond the one corresponding to the critical current, one observes a relatively well correlated hexagonal lattice. The channels and the plastic flow at relatively low velocities are explained by influence of pinning on the basis of theoretical arguments [8] and confirmed by numerous simulations [8][9][10][11][12]. At high velocity of the moving lattice (corresponding to high electric field), the influence of disorder is expected to diminish and a "moving Bragg glass" appears [8,13].…”

“…Since the theoretical prediction of the moving Bragg glass exhibiting transverse peak effect [13], a lot of effort has been put into the simulation of the high driving force phase of the moving vortex system [10][11][12]. In particular it was found [10] that as the driving force increases (or disorder decreases) the vortex lattice suddenly changes orientation for a period of time and then returns to a "regular" drift mode.…”

Dynamic transition in current-driven disordered flux-line lattice in single-crystal of Bi-2212

“…Such crossover has been observed in colloid [6] and superconducting vortex systems [8]. A plastic flow is observed in a large number of experiments and numerical simulations studies of particle motion in a random pinning disorder [6,9,10,[11][12][13][14][15][16]. The largest numbers of results from the numerical simulations are the evolution of current-voltage characteristics and dynamic phase diagram.…”

Peak Effect in Superconductors: Absence of Phase Transition and Possibility of Jamming in Vortex Matter

“…As shown in Ref. [51], δI dis (b) increases rapidly in the PE region implying that larger currents are required to anneal the defects. This is reflected in the slow growth of V (I) curve for high fields, which consequently cross the curves for low fields as shown in Fig.…”