%0 Conference Paper
%A Wessels, Philipp
%A Ewald, Johannes
%A Wieland, Marek
%A Nisius, Thomas
%A Vogel, Andreas
%A Abbati, Gennaro
%A Baumbach, Stefan
%A Overbuschmann, Johannes
%A Viefhaus, Jens
%A Meier, Guido
%A Wilhein, Thomas
%A Drescher, Markus
%T Time-resolved X-ray Microscopy of Domain pattern Destruction and Recovery via Non-Equilibrium uniform Magnetization states in Permalloy Vortex Elements at the P04 Beamline of PETRA III
%I University of Hamburg
%M PUBDB-2014-04819
%D 2014
%X Picosecond magnetization dynamics of small permalloy (Ni80Fe20) elements has been investigated with a new, mobile full-field transmission microscope at the soft X-ray beamline P04 of the high brilliance synchrotron radiation source PETRA III. The experiment uses intense magnetic Oersted field pulses with up to 80 mT peak amplitude to force vortex flux-closure magnetization patterns into a homogeneously magnetized state by aligning the majority of the magnetization along a single axis. The evolution of the domain pattern destruction and recovery could be monitored directly in space and in time and is supported by micromagnetic simulations. On the rising edge of the magnetic field pulse, high velocities of the central vortex core were discovered exceeding 1 km/s and thus also exceeding the threshold velocity of vortex core switching. Moreover, some vortices show a stable chirality and polarity after recovery.The newly constructed soft X-ray microscope generates a homogeneous flat-top illumination field of 20 μm diameter using a grating condenser. A tilted nanostructured magnetic sample can be excited either by making use of a mobile synchronized femtosecond laser system or by a picosecond electric current pulse via a coplanar waveguide. The transmitted light of the sample plane is directly imaged by a micro zone plate with 65 nm resolution onto a 2D gateable X-ray detector to select one particular bunch in the storage ring that probes the time evolution of the dynamic information successively via X-ray magnetic circular dichroism (XMCD) spectromicroscopy in a pump-probe scheme. The time-resolution is fundamentally limited to 90 ps FWHM by the PETRA III bunch length.
%B 59th Annual Magnetism and Magnetic Materials Conference
%C 3 Nov 2014 - 7 Nov 2014, Honolulu (USA)
Y2 3 Nov 2014 - 7 Nov 2014
M2 Honolulu, USA
%F PUB:(DE-HGF)6
%9 Conference Presentation
%U https://bib-pubdb1.desy.de/record/205421