Vortex Dynamic Phases in Type II Superconducting Strips with Regular and Flattened Triangular Pinning Arrays

Abstract

The dynamic behavior of vortices in type II superconducting infinite strips is simulated with two types of triangular pinning lattices: the regular one and a flattened triangular array that mimics the vortex lattice in a superconducting strip in the absence of a pinning array. The calculations were made at zero temperature and perpendicular magnetic field. The size effects are investigated for several strip widths maintaining the density and size of pinning centers unchanged. A driving force is applied in the infinite direction to analyze the depinning process and the different dynamic regimes. For the regular triangular pinning lattice, we found that there is a great richness of vortex dynamical phases because depending on strip width, part of the vortices may stabilize in different interstitial positions and the depinning process depends on the commensurability of each vortex chain. For the flattened triangular lattice, the system exhibits one ordered moving phase for narrower strips and two moving phases for the larger strip. As the transport force increases, vortices in the larger strip go from a disordered to an ordered phase. Moreover, the flattened lattice shows a much higher critical depinning force than the regular one due to commensurability effects.

Dynamic Phases and Reentrant Hall Effect for Vortices and Skyrmions on Periodic Pinning Arrays

“…Other aspects have also been explored such as adding asymmetry to the arrays [21], introducing local heating in order to produce both S-shaped and N-shaped velocity-force curves in analogy to those found in conduction curves for semiconductors [22], and inducing density wave propagation [23]. Numerous other studies of superconducting vortices in periodic pinning arrays have revealed multiple depinning transitions, the flow of interstitials, kink flow, and multiple step jumps in the velocity-force curves [24,25,26,27,28,29,30,31,32] Previous studies involved strictly overdamped particles; however, non-dissipative forces can also arise, such as the Magnus gyrotropic force [33,34], which creates a velocity component perpendicular to the forces acting on the particle [33,35]. In superconducting vortex systems, Magnus forces are possible, and experiments have found evidence for transverse motion or the vortex Hall effect [36], with more recent observations showing vortex Hall angles of up to 45 • in certain types of superconducting systems [37].…”