Magneto-Chiral Anisotropy in Josephson Diode Effect of All-Metallic Lateral Junctions with Interfacial Rashba Spin-Orbit Coupling

TL;DR

This paper investigates how interfacial Rashba spin-orbit coupling influences the Josephson diode effect in all-metallic lateral junctions, revealing magneto-chiral anisotropy linked to interface symmetry breaking.

Contribution

It demonstrates the impact of interfacial Rashba SOC on the Josephson diode effect and distinguishes effects caused by symmetry breaking from those due to stray magnetic fields.

Findings

Devices with Fe/Pt and Cu/Pt weak links show diode effect with magneto-chiral anisotropy.

Plain Cu-layer weak link exhibits an axis-symmetric diode effect.

Fraunhofer patterns reveal inverted hysteresis due to stray fields from vortex pinning.

Abstract

We explore the role of interfacial Rashba spin-orbit coupling (SOC) for the Josephson diode effect in all-metal diffusive Josephson junctions. Devices with Fe/Pt and Cu/Pt weak links between Nb leads reveal a Josephson diode effect in an in-plane magnetic field with magneto-chiral anisotropy according to the point symmetry of Rashba SOC. The Rashba SOC originates from inversion symmetry breaking at the metal-metal interfaces. A control sample with a plain Cu-layer as weak link, in contrast, exhibits an axis-symmetric diode effect. The Fraunhofer patterns display an apparent inverted hysteresis which can be traced back to stray fields resulting from the conventional hysteretic vortex pinning in the Nb contacts.