Nonuniform Self-Organized Dynamical States in Superconductors with Periodic Pinning

TL;DR

This paper investigates how magnetic flux in superconductors with periodic pinning arrays exhibits negative differential resistivity, leading to unstable flux flow and the formation of complex self-organized dynamical structures.

Contribution

It reveals the emergence of nonuniform self-organized states in superconductors caused by negative differential resistivity due to vortex heating.

Findings

Negative differential resistivity causes flux flow instability.

Domain and filamentary structures form during NDR regions.

Self-organized 2D dynamical states arise from combined NDR types.

Abstract

We consider magnetic flux moving in superconductors with periodic pinning arrays. We show that sample heating by moving vortices produces negative differential resistivity (NDR) of both N and S type (i.e., N- and S-shaped) in the voltage-current characteristic (VI curve). The uniform flux flow state is unstable in the NDR region of the VI curve. Domain structures appear during the NDR part of the VI curve of an N type, while a filamentary instability is observed for the NDR of an S type. The simultaneous existence of the NDR of both types gives rise to the appearance of striking self-organized (both stationary and non-stationary) two-dimensional dynamical structures.