Spin torque resonant vortex core expulsion for an efficient radio-frequency detection scheme

TL;DR

This paper introduces a novel spin-torque resonant vortex core expulsion mechanism in magnetic tunnel junctions, enabling efficient, tunable RF detection with stable voltage output independent of RF power levels.

Contribution

It presents a new resonant vortex core expulsion effect that enhances RF detection efficiency and tunability beyond conventional spin-torque diode methods.

Findings

Vortex core expulsion causes large resistance change.

The effect is highly tunable and maintains voltage output regardless of RF power.

Potential for next-generation nanoscale RF detectors.

Abstract

Spin-polarised radio-frequency currents, whose frequency is equal to that of the gyrotropic mode, will cause an excitation of the core of a magnetic vortex confined in a magnetic tunnel junction. When the excitation radius of the vortex core is greater than that of the junction radius, vortex core expulsion is observed, leading to a large change in resistance, as the layer enters a predominantly uniform magnetisation state. Unlike the conventional spin-torque diode effect, this highly tunable resonant effect will generate a voltage which does not decrease as a function of rf power, and has the potential to form the basis of a new generation of tunable nanoscale radio-frequency detectors.