Magnetic Vortex Core Oscillations in Multi Point Contact Spin Valve Stacks

We study gyration frequencies of magnetic vortices in double point contact spin valve stacks by combining Thiele's equation and micromagnetics. We apply numerical integration and error control techniques to find stable, in-plane orbits in the rigid vortex model as a function of applied current densities and point contact geometry. The results show that the velocity of the vortex depends strongly on the restoring potential. The angular velocity (i.e., frequency) increases as the radius of one of the point contacts is decreased, due to a narrower current density profile. In addition we observe that multiple oscillation trajectories are possible depending on the current distribution between the point contacts.