Magnetic moment manipulation by a Josephson current

TL;DR

This paper explores how a Josephson junction with a non-centrosymmetric ferromagnet as the weak link enables control of magnetic moments through superconducting currents, revealing complex feedback effects and anomalies near resonance.

Contribution

It introduces a novel mechanism where a.c. Josephson effects induce magnetic precession, leading to unique current-phase relation anomalies in such hybrid systems.

Findings

Magnetic precession is driven by the a.c. Josephson effect.

Current-phase relations exhibit anomalies like second harmonic generation.

Enhanced effects occur near ferromagnetic resonance frequency.

Abstract

We consider a Josephson junction where the weak-link is formed by a non-centrosymmetric ferromagnet. In such a junction, the superconducting current acts as a direct driving force on the magnetic moment. We show that the a.c. Josephson effect generates a magnetic precession providing then a feedback to the current. Magnetic dynamics result in several anomalies of current-phase relations (second harmonic, dissipative current) which are strongly enhanced near the ferromagnetic resonance frequency.