  We propose a method that allows power conversion from DC magnetic fields to
AC electric voltages using domain wall (DW) motion in ferromagnetic nanowires.
The device concept relies on spinmotive force, voltage generation due to
magnetization dynamics. Sinusoidal modulation of the nanowire width introduces
a periodic potential for a DW the gradient of which exerts variable pressure on
the traveling DW. This results in time variation of the DW precession frequency
and the associated voltage. Using a one-dimensional model we show that the
frequency and amplitude of the AC outputs can be tuned by the DC magnetic
fields and wire-design.
