Effects of current on nanoscale ring-shaped magnetic tunnel junctions

TL;DR

This paper investigates how electric currents induce magnetization switching in nanoscale ring-shaped magnetic tunnel junctions, highlighting the role of spin torque over magnetic fields, with experimental and simulation support.

Contribution

It provides the first detailed analysis of current-driven switching mechanisms in nanoscale ring-shaped magnetic tunnel junctions, emphasizing spin torque effects.

Findings

Switching occurs at current densities above 6×10^6 A/cm^2.

Spin torque is identified as the primary switching mechanism.

Magnetization states switch between parallel and antiparallel configurations.

Abstract

We report the observation and micromagnetic analysis of current-driven magnetization switching in nanoscale ring-shaped magnetic tunnel junctions. When the electric current density exceeds a critical value of the order of $6\times 10^{6}$A/cm$^2$, the magnetization of the two magnetic rings can be switched back and forth between parallel and antiparallel onion states. Theoretical analysis and micromagnetic simulation show that the dominant mechanism for the observed current-driven switching is the spin torque rather than the current-induced circular Oersted field.