Magnetic skyrmion resonance and characterization in magnetic tunnel junctions

We explore a spectroscopic method of characterizing individual Neel-type magnetic skyrmions through their resonant dynamics within a magnetic tunnel junction structure. Using micromagnetic simulations and taking thermal effects into account, we show that magnetic skyrmion resonances and their evolution in the presence of an external magnetic field can be efficiently probed with a current-induced spin-transfer torque and measured via tunnel magnetoresistance, with a magnetic noise level comparable to that found in standard ferromagnetic resonance measurements. We find that the skyrmion resonance dispersion is an accurate probe for skyrmion size, with potentially higher resolution than standard magnetic imaging techniques. This result could lead to non-invasive, on-chip skyrmion detection and measurement in skyrmion-based memory and logic architectures.