  The pyrochlore compounds Ho2Ti2O7 and Dy2Ti2O7 show an exotic form of
magnetism called the spin ice state, resulting from the interplay between
geometrical frustration and ferromagnetic coupling. A fascinating feature of
this state is the appearance of magnetic monopoles as emergent excitations
above the degenerate ground state. Over the past years, strong effort has been
devoted to the investigation of these monopoles and other properties of the
spin ice state in bulk crystals. A tantalising prospect is to incorporate spin
ice materials into devices for spintronics and devices that can manipulate the
magnetic monopoles. This would require the availability of spin ice thin films.
Here, we report the fabrication of Ho2Ti2O7 thin films using pulsed laser
deposition. These films not only show a high crystalline quality, but also
exhibit the hallmarks of a spin ice: a pronounced magnetic anisotropy and an
intermediate plateau in the magnetisation along the [111] crystal direction.
