  Magnetically Modulated Optical Nanoprobes (MagMOONs) are magnetic particles
that indicate their angular orientation by emitting varying intensities of
light for different orientations and have shown promise for a variety of
applications. In this letter we describe a new method to fabricate uniform
magnetic half-shell particles that can be used as MagMOONs. Cobalt was
deposited onto commercially made polystyrene nanospheres and microspheres,
using ultrahigh vacuum vapor deposition, producing particles with uniform size,
shape and magnetic content. Additionally, the coercivity of the cobalt
deposited on the nanospheres was enhanced compared to its bulk value.
