We investigate electron shuttling in three-terminal nanoelectromechanocal
device built on a movable metallic rod oscillating between two drains. The
device shows a double-well shaped electromechanical potential tunable by a
source-drain bias voltage. Four stationary regimes controllable by the bias are
found for this device: (i) single stable fixed point, (ii) two stable fixed
points, (iii) two limiting cycles, and (iv) single limiting cycle. In the
presence of perpendicular magnetic field the Lorentz force makes possible
switching from one electromechanical state to another. The mechanism of tunable
transitions between various stable regimes based on the interplay between
voltage controlled electromechanical instability and magnetically controlled
switching is suggested. The switching phenomenon is implemented for achieving
both a reliable \emph{active} current switch and sensoring of small variations
of magnetic field.Comment: 11 pages, 4 figure
