Assembly and imaging of submicron ferromagnets in GaAs (invited)

Submicron room-temperature ferromagnets are formed in GaAs semiconductors through a simple process of ion implantation and subsequent heat treatment. The ferromagnetic structures are studied using magnetic force microscopy. Magnetization switching of single-domain particles has been directly imaged in applied magnetic fields. In order to understand the images of magnetic structures taken under external fields, we have characterized the magnetic force microscopy (MFM) probes by imaging microfabricated current-carrying strips in applied magnetic fields. Patterned micrometer scale lines containing submicron magnetic structures on GaAs are fabricated using lithography in conjunction with broad beam ion implantation.