MFM analysis of the magnetization process in L10–A1 FePt patterned film fabricated by ion irradiation

Abstract Ga + ions at a dose of 0.1 at.% (1.5 × 10 14 ions cm −2 ) were irradiated by focused ion beam (FIB) onto L 1 0 FePt films with a [0 0 1] crystalline texture normal to the film plane, and two-dimensional patterns composed of squares with high-coercivity ( L 1 0 structure, 300 × 300 nm 2 and 100 × 100 nm 2 ) separated by a soft magnetic region ( A 1 structure) 100 nm wide were fabricated. The magnetic domain structure of patterned film was observed by in-field magnetic force microscopy (MFM). In the remanent state, the domain with magnetization normal to the film surface was observed in the central part of the L 1 0 square, while the narrow domain with reversed magnetization is at the circumference of the square. The magnetization process is discussed based on the MFM observations.