X-ray holographic imaging of dot patterned perpendicular magnetic structures

Dot patterned magnetic data storage media with perpendicular magnetic anisotropy (PMA) are among the most promising candidates for future storage technology that is threatened by the superparamagnetic limit in conventional hard disk media. There is therefore industrial and fundamental scientific interest for dynamic and static imaging of spin structures in these materials. Of particular interest are domain wall movement and domain switching processes. X-ray holography is a well suited imaging technology due to the immunity to drift, the absence of any cross talk between the excitation system and the imaging system and due to the perspective to take single shot time resolved images at free electron lasers. We present first holographic images of PMA material disks. The image quality was considerably improved by an advanced reconstruction algorithm accounting for finite gaps in the path of the X-rays.