Reverse-domain superconductivity in superconductor-ferromagnet hybrids: effect of a vortex-free channel on the symmetry of I-V characteristics

TL;DR

This paper experimentally shows that a single ferromagnetic domain wall can induce diode-like asymmetry in the I-V characteristics of a superconductor-ferromagnet hybrid, due to vortex-free channels affecting current flow.

Contribution

It reveals how a ferromagnetic domain wall can create vortex-free channels that induce current asymmetry in superconductor-ferromagnet hybrids, a novel effect.

Findings

Presence of a domain wall induces I-V asymmetry.

Vortex-free channels enable dissipationless current flow.

Effect depends on current polarity and magnetic field.

Abstract

We demonstrate experimentally that the presence of a single domain wall in an underlying ferromagnetic BaFe_{12}O_{19} substrate can induce a considerable asymmetry in the current (I) - voltage (V) characteristics of a superconducting Al bridge. The observed diode-like effect, i.e. polarity-dependent critical current, is associated with the formation of a vortex-free channel inside the superconducting area which increases the total current flowing through the superconducting bridge without dissipation. The vortex-free region appears only for a certain sign of the injected current and for a limited range of the external magnetic field.