Local “annealing” and domain patterning of amorphous films by He-ion irradiation

The magnetic anisotropy in amorphous soft magnetic FeCoSiB films is modified by He-ion irradiation. A realignment of uniaxial anisotropy depending on the applied field direction in the irradiated areas is observed by magnetometry and complementary domain observation by Kerr microscopy. Using irradiation together with photolithography the films were treated locally, resulting in ‘anisotropy patterned’ structures. Complicated periodic domain patterns form due to the confined anisotropy distribution. Overall magnetic properties and domain patterns can be adjusted.