  We report numerical and analytical studies of the reversal of the magnetic
moment of a single-domain magnetic particle by a circularly polarized ac field
of time-dependent frequency. For the time-linear frequency sweep, the phase
diagrams are computed that illustrate the dependence of the reversal on the
frequency sweep rate v, the amplitude of the ac field h, the magnetic
anisotropy field d, and the damping parameter alpha. It is shown that the most
efficient magnetization reversal requires a non-linear time dependence of the
frequency, omega(t), for which an exact analytical formula is derived with
account of damping. The necessary condition of the reversal is h > alpha d.
Implementation of a small-scale magnetization reversal is proposed in which a
nanomagnet is electromagnetically coupled to two weak superconducting links
controlled by the voltage. Dynamics of such a system is analyzed with account
of the back effect of the magnet on the superconducting links.
