Irradiation induced magnetic patterning of soft-magnetic thin films

Numerous applications of ferromagnetic materials in magneto-electronics are based on multi-layer thin film technology. For most of the relevant applications the magnetic films are patterned by lithographic processes, which result in isolated magnetic elements. Here, we demonstrate the lateral alteration of magnetic properties of soft-magnetic thin films by ion irradiation. In contrast to traditionally patterned thin films, the interaction within the patterned structure occurs through direct magnetic exchange, resulting in novel effective magnetic properties and magnetization states fundamentally differing from conventionally magnetic thin films.
The method and a summary of ion-induced modifications of fundamental magnetic properties of different materials will be shown on single layer crystalline and amorphous thin films, and multi-layered systems. Examples include laterally modulated saturation polarization as well as locally varying magnetic anisotropy alignment, both resembling anisotropic as well as patterned soft-magnetic film behavior. The scaling behavior for the resulting structures will be discussed and the data will be compared to effects known so far only from multi-layered magnetic layers. Moreover it will be shown, that not only the regular static magnetic behavior, but also the magnetization dynamics of systems can be tuned and laterally modified by ion irradiation.
The local modulation of magnetic properties opens exciting new opportunities to the tuning of the integral properties of soft-magnetic thin films and establishes an additional path to thin film magnetic structures with novel functionality.

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J. McCord, L. Schultz, J. Fassbender, Adv. Mater., accepted for publication.