TY  - JOUR
A1  - von Reppert, Alexander
A1  - Willig, Lisa
A1  - Pudell, Jan-Etienne
A1  - Roessle, M.
A1  - Leitenberger, Wolfram
A1  - Herzog, Marc
A1  - Ganss, F.
A1  - Hellwig, O.
A1  - Bargheer, Matias
T1  - Ultrafast laser generated strain in granular and continuous FePt thin films
T2  - Applied physics letters
N2  - We employ ultrafast X-ray diffraction to compare the lattice dynamics of laser-excited continuous and granular FePt films on MgO (100) substrates. Contrary to recent results on free-standing granular films, we observe in both cases a pronounced and long-lasting out-of-plane expansion. We attribute this discrepancy to the in-plane expansion, which is suppressed by symmetry in continuous films. Granular films on substrates are less constrained and already show a reduced out-of-plane contraction. Via the Poisson effect, out-of-plane contractions drive in-plane expansion and vice versa. Consistently, the granular film exhibits a short-lived out-of-plane contraction driven by ultrafast demagnetization which is followed by a reduced and delayed expansion. From the acoustic reflections of the observed strain waves at the film-substrate interface, we extract a 13% reduction of the elastic constants in thin 10 nm FePt films compared to bulk-like samples. (C) 2018 Author(s).
Y1  - 2018
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/51956
SN  - 0003-6951
SN  - 1077-3118
VL  - 113
IS  - 12
PB  - American Institute of Physics
CY  - Melville
ER  -