  The core of a ferromagnetic vortex domain creates a strong, localized
magnetic field which can be manipulated on nanosecond timescales, providing a
platform for addressing and controlling individual nitrogen-vacancy center
spins in diamond at room temperature, with nanometer-scale resolution. First,
we show that the ferromagnetic vortex can be driven into proximity with a
nitrogen-vacancy defect using small applied magnetic fields, inducing
significant nitrogen-vacancy spin splitting. Second, we find that the magnetic
field gradient produced by the vortex is sufficient to address spins separated
by nanometer length scales. By applying a microwave-frequency magnetic field,
we drive both the vortex and the nitrogen-vacancy spins, resulting in enhanced
coherent rotation of the spin state. Finally we demonstrate that by driving the
vortex on fast timescales, sequential addressing and coherent manipulation of
spins is possible on $\sim100$ ns timescales.
