Modification of the perpendicular anisotropy in synthetic antiferromagnets by global and local ion beam irradiation

We investigate sputter deposited synthetic antiferromagnets consisting of Co/Pt multilayers with perpendicular anisotropy. Repeated multilayer-blocks are antiferromagnetically coupled to each other via Ru interlayers. This complex sample structure allows an exact tuning of the energy contributions perpendicular anisotropy, interlayer exchange and demagnetization: Varying repeats within the Co/Pt multilayers (X) or a different number of multilayer-blocks (N) lead to various magnetic phases and 3-dimensional textures [1].
By ion beam irradiation we can change the balance of these energy contributions due to an intermixing at the interfaces. With this we can realize various magnetic phases within one and the same sample and by local irradiation we can even achieve a lateral coexistence of different magnetic phases.
We will present our investigations of globally and locally irradiated synthetic antiferromagnet’s field reversal behaviour, using vibrating sample magnetometry and high resolution magnetic force microscopy.
[1] O. Hellwig et al., J. Magn. Magn. Mater. 319, 13 (2007)