  Artificial spin ices (ASI) have been widely investigated as magnetic
metamaterials with exotic properties governed by their geometries. In parallel,
interest in X-ray photon orbital angular momentum (OAM) has been rapidly
growing. Here we show that a square ASI with a programmed topological defect, a
double edge dislocation, imparts OAM to scattered X-rays. Unlike single
dislocations, a double dislocation does not introduce magnetic frustration, and
the ASI equilibrates to its antiferromagnetic (AF) ground state. The
topological charge of the defect differs with respect to the structural and
magnetic order; thus, X-ray diffraction from the ASI produces photons with even
and odd OAM quantum numbers at the structural and AF Bragg conditions,
respectively. The magnetic transitions of the ASI allow the AF OAM beams to be
switched on and off by modest variations of temperature and applied magnetic
field. These results demonstrate ASIs can serve as metasurfaces for
reconfigurable X-ray optics that could enable selective probes of electronic
and magnetic properties.
