  We report an artificial geometrically frustrated magnet based on an array of
lithographically fabricated single-domain ferromagnetic islands. The islands
are arranged such that the dipole interactions create a two-dimensional
analogue to spin ice. Images of the magnetic moments of individual elements in
this correlated system allow us to study the local accommodation of
frustration. We see both ice-like short-range correlations and an absence of
long-range correlations, behaviour which is strikingly similar to the
lowtemperature state of spin ice. These results demonstrate that artificial
frustrated magnets can provide an uncharted arena in which the physics of
frustration can be directly visualized.
