Regensburg 2010 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
MA: Fachverband Magnetismus
MA 31: Surface Magnetism / Magnetic Imaging II
MA 31.11: Talk
Thursday, March 25, 2010, 18:00–18:15, H23
Imaging the in-plane magnetisation of Co microstructures by soft x-ray holography — •Carsten Tieg1, Robert Frömter2, Daniel Stickler2, Sebastian Hankemeier2, André Kobs2, Hans Peter Oepen2, Simone Streit-Nierobisch3, Christian Gutt3, and Gerhard Grübel3 — 1Helmholtz-Zentrum für Materialien und Energie GmbH, Berlin, Germany — 2Institut für Angewandte Physik, Universität Hamburg, Hamburg, Germany — 3Deutsches Elektronen-Synchrotron, Hamburg, Germany
We report how Fourier transform holography (FTH) experiments can be used to image the magnetic state of isolated Co microstructures. Up to now, FTH imaging has been applied solely to magnetic systems with out-of-plane magnetisation, owing to the large magnetic sensitivity in transmission geometry at normal incidence. The angular dependence of the x-ray magnetic circular dichroism (XMCD) does not allow to sense the in-plane magnetization with the standard holography sample design, containing reference holes fabricated perpendicularly to the membrane surface by focussed ion beam milling. Samples with an in-plane magnetisation have to be imaged at off-normal incidence to obtain XMCD, so the transmission of the high-aspect-ratio reference holes is lost. The solution is to mill the reference holes at the same tilt angle that is used for imaging. We have used this scheme to image a 2 × 2 µm2 Co element with 20 nm thickness. We found a multi domain state that differs from the expected Landau state for this element size. We attribute the observed higher-energy domain state to the presence of pinning centers and to imperfections of the shape of the Co element.