Tailoring Magnetic Properties Using Ion Beam Irradiation

Magnetism is a collective phenomenon. Hence, local variations on the nanoscale of material properties, which act on the magnetic properties, affect the overall magnetism in an intriguing way. In particular important are the length scales on which a material property changes. These might be related to the exchange length, the domain wall width, a typical roughness correlation length, or a length scale introduced by patterning of the material.
Ion beam erosion can be applied to create well ordered substrate ripples with nanometer periodicity. These artificially created templates serve as a source of a predefined surface morphology and hence allow for the investigation of roughness phenomena. In contrast to that post ion beam irradiation can be used to tailor the magnetic properties of conventional thin films and multilayers. The resulting magnetic properties are neither present in non-implanted nor in homogeneously implanted films. In both cases the magnetic properties depend sensitively on the artificially introduced length scale. Ferromagnetic resonance data of irradiated Py/Ta multilayers as well as Co and Fe thin films on ripple substrates are discussed.