Theory of I-V Characteristics of Magnetic Josephson Junctions

TL;DR

This paper analyzes the electrical behavior of magnetic Josephson junctions, revealing a critical current-induced resistance jump influenced by spin polarization and magnet thickness, with an analogy to superconducting Josephson effects.

Contribution

It introduces a theoretical framework for understanding the I-V characteristics of magnetic Josephson junctions, highlighting the role of spin polarization and magnetic configuration.

Findings

Resistance increases sharply beyond a critical current

Large resistance change occurs with strong spin polarization

Behavior analogous to Josephson junctions in superconductors

Abstract

We analyze the electrical characteristics of a circuit consisting of a free thin-film magnetic layer and source and drain electrodes that have opposite magnetization orientations along the free magnet's two hard directions. We find that when the circuit's current exceeds a critical value there is a sudden resistance increase which can be large in relative terms if the currents to source or drain are strongly spin polarized and the free magnet is thin. This behavior can be partly understood in terms of a close analogy between the magnetic circuit and a Josephson junction.