  We present a design for a switchable nanomagnetic atom mirror formed by an
array of 180{\deg} domain walls confined within Ni80Fe20 planar nanowires. A
simple analytical model is developed which allows the magnetic field produced
by the domain wall array to be calculated. This model is then used to optimize
the geometry of the nanowires so as to maximize the reflectivity of the atom
mirror. We then describe the fabrication of a nanowire array and characterize
its magnetic behavior using magneto-optic Kerr effect magnetometry, scanning
Hall probe microscopy and micromagnetic simulations, demonstrating how the
mobility of the domain walls allow the atom mirror to be switched "on" and
"off" in a manner which would be impossible for conventional designs. Finally,
we model the reflection of 87Rb atoms from the atom mirror's surface, showing
that our design is well suited for investigating interactions between domain
walls and cold atoms.
