Magnetic force microscopy of single‐domain single‐crystal iron particles with uniaxial surface anisotropy

Lithographic patterning techniques have been used to fabricate arrays of submicron particles from a [110] single‐crystal iron thin film with a strong uniaxial surface anisotropy and with an easy axis of magnetization lying in the [001] direction (in the plane of the film). Magnetic force microscopy images indicate that these islands are single domain over a wide range of island shapes and sizes. The uniaxial surface anisotropy is stronger than the shape anisotropy for the island geometries used, so the easy axes of the islands all lie roughly in the [001] direction, regardless of the island shape. Magnetic force images were also taken as both the magnetic tip and sample were subjected to a gradually increasing externally applied field. This technique allows us to monitor the magnetization reversal of individual islands and provides a direct measure of their switching fields.