Submicron (100–500 nm) room-temperature ferromagnets of MnAs have been successfully incorporated into GaAs semiconductor substrates by Mn+
ion implantation and subsequent heat treatment at 920 °C for 1 s in a nitrogen gas. Atomic force microscopy indicates an epitaxial relation of  oriented hexagonal MnAs crystallites on (001) GaAs substrates: [11 0]MnAs∥GaAs.
A stronger shape anisotropy along GaAs
is observed for the smaller crystallites. Magnetic characterizations by superconducting quantum interference device reveal uniaxial in-plane magnetic anisotropy of the sample. Magnetic force microscopy imaging shows that the uniaxial magnetic anisotropy comes from the alignment of magnetic dipoles along the magnetic easy [11 20] axis of MnAs, which is parallel to GaAs.
© 1998 American Institute of Physics.