Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 27: Magnetization / Demagnetization Dynamics I

MA 27.5: Vortrag

Mittwoch, 18. März 2015, 10:30–10:45, EB 301

Ultrafast Generation of Magnetic Ordering in a First Order Phase Transition — •Robert Carley¹, Sebastian Carron⁶, Tyler Chase⁴, Bruce Clemens⁴, Georgi Dakovski⁶, Eric Fullerton⁵, Patrick Granitzka⁴, Alexander Gray³, Stefan Günther², Daniel Higley⁴, Manuel Izquierdo¹, Emmanuelle Jal³, Loic Le Guyader⁷, Joel Li⁴, Serguei Molodtsov¹, Mike Minitti⁶, Ankush Mitra⁶, Alexander Reid³, William Schlotter⁶, Vojtech Uhlir⁵, Joachim Stöhr³, Hermann Dürr³, Christian Back², and Andreas Scherz¹ — ¹European XFEL, Hamburg, Germany — ²Universität Regensburg, Germany — ³SIMES, Stanford, California, USA — ⁴Stanford University, California, USA — ⁵University of California San Diego, USA — ⁶LCLS, Stanford, California, USA — ⁷HZB, Berlin, Germany

We report on recent experimental studies of the laser-driven antiferromagnetic (AFM) to ferromagnetic (FM) phase transition in FeRh using the time-, element-, and spatially resolving technique of resonant x-ray diffraction (tr-RXD) at the Fe L3 edge. FeRh undergoes a prototypical first order phase transition where the magnetization is the order parameter. The AFM to FM transition is accompanied by an isotropic lattice expansion. Time-resolved magneto-optical Kerr effect measurements suggest FM generation on sub-picosecond time scales, indicating an electronic process. In contrast, monitoring the lattice with time-resolved hard x-ray diffraction reveals nucleation and growth of FM regions on 10ps time-scales. This work aims to establish if the electronic system or the lattice drives the phase transition.