The vortex steady-state oscillation frequency vs. current. The nanodot thickness L is 5 nm (1), 7 nm (2), and 10 nm (3), and radius is R = 100 nm. The frequency is shown within the current range of the stable vortex steady-state orbit, Jc 1 < J < Jc 2. Solid black lines are calculations by Equation 5; red squares mark the simulated points. Inset: the nonlinear vortex frequency coefficient vs. the dot thickness for R = 100 nm and J = 0 accounting all energy contributions (1) and only magnetostatic contribution (2).