Single magnetic skyrmion creation, detection, and dynamics within a magnetic tunnel junction*

We experimentally demonstrate the deterministic creation of a stable topological spin texture in the free layer of a magnetic tunnel junction at cryogenic temperatures. Through simultaneous measurements of tunnel magnetoresistance and spin-polarized current-induced magnetic resonance, we find that the spin texture is characterized by a field-dependent intermediate junction resistance and a unique magnetic resonance signature. Comparing our findings to micromagnetic simulations, we confirm that the spin texture transition is best described by the nucleation of a single Bloch-type skyrmion in the free layer, aided by a spatially nonuniform stray field from surrounding magnetic layers. We subsequently identify the skyrmion breathing mode in the resonance spectrum and obtain an estimate for the skyrmion diameter at zero field of 75 nm. This result is the first confirmation that magnetic tunnel junctions are viable candidates for skyrmion-based memory and logic architectures could lead to non-invasive, on-chip skyrmion measurement and detection.