Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 52: Poster II
MA 52.35: Poster
Donnerstag, 15. März 2018, 15:00–18:00, Poster C
Studying the effect of anisotropy on lattice and magnetization dynamics in FePt — •Lisa Willig1,3, Paul Haberjoh1, Jan-Etienne Pudell1, Olav Hellwig2, Alexander von Reppert1, and Matias Bargheer1,3 — 1Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany — 2Institut für Physik, Technische Universität Chemnitz, Chemnitz, Germany — 3Helmholtz-Zentrum Berlin, Berlin, Germany
Here we compare the response of two nanoscopic FePt specimen: granular and continuous films of comparable size upon fs-laser excitation. The FePt particles of the granular film are embedded in carbon matrix and exhibit a much larger out of plane magnetic anisotropy, which is desirable for heat assisted magnetic recording. Ultrafast X-Ray diffraction with a 200 fs time-resolution is used to monitor the lattice dynamics and energy flow in both films. Marked differences appear in the initial strain buildup: The nanoscopic granular film exhibits a delayed onset and strongly reduced amplitude in the out of plane expansion compared to the immediate expansion of the homogeneously excited continuous film, where all in-plane stresses are intrinsically balanced. We complement our findings of the lattice dynamics with magnetization measurements via time-resolved MOKE to present lattice and magnetization of this technologically relevant material under comparable conditions.