Observation of droplet soliton drift resonances in a spin-transfer-torque nanocontact to a ferromagnetic thin film

Magnetic droplet solitons are nonlinear dynamical modes that can be excited in a thin film with perpendicular magnetic anisotropy with a spin-transfer torque. Although droplet solitons have been proved to be stable with a hysteretic response to applied currents and magnetic fields at low temperature, measurements at room temperature indicate less stability and reduced hysteresis width. Here, we report evidence of droplet soliton drift instabilities, leading to drift resonances, at room temperature that explains their lower stability. Micromagnetic simulations show that the drift instability is produced by an effective-field asymmetry in the nanocontact region that can have different origins.