Magnetic Domain Wall Oscillator With Current-Perpendicular-to-Plane Geometry

By means of analytical 1-D model and full micromagnetic simulation, we investigated the magnetic domain wall (DW) oscillator with current-perpendicular-to-plane geometry. We found that the DW oscillation frequency linearly increases with the applying current density, but drops above a certain threshold. This frequency drop is caused by the deformation of DW due to spin-transfer torque. We found that by applying an external perpendicular magnetic field in addition to the current, this deformation and the frequency drop can be suppressed, which allows obtaining a reliable frequency range for the device application.