  Using the ultra low damping NiMnSb half-Heusler alloy patterned into
vortex-state magnetic nano-dots, we demonstrate a new concept of non-volatile
memory controlled by the frequency. A perpendicular bias magnetic field is used
to split the frequency of the vortex core gyrotropic rotation into two distinct
frequencies, depending on the sign of the vortex core polarity $p=\pm1$ inside
the dot. A magnetic resonance force microscope and microwave pulses applied at
one of these two resonant frequencies allow for local and deterministic
addressing of binary information (core polarity).
