Regensburg 2022 – scientific programme
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MA: Fachverband Magnetismus
MA 35: Poster 2
MA 35.41: Poster
Thursday, September 8, 2022, 16:00–18:00, P4
Ultrafast optical Spectroscopy of LaMnO3/SrMnO3 Superlattices — •Tim Titze, Leonard Schueler, Jannik Brumm, Vitaly Bruchmann-Bamberg, Vasily Moshnyaga, Daniel Steil, and Stefan Mathias — I. Physikalisches Institut, Goettingen, Germany
We investigate photoinduced dynamics of a LaMnO3/SrMnO3 superlattice, using transient reflectivity Δ R/R at various temperatures. The superlattice exhibits a low-TC ferromagnetic (FM) phase below TC,LMO=200 K with a bulk-LMO-like behavior. Further, Keunecke et al. reported on a high-TC interfacial quasi-2D FM phase below TC,2D=350 K that results from an LMO to SMO charge transfer during sample growth [1].
By studying the system response on timescales from fs to ns we aim to determine whether the 2D interfacial phase shows a distinctly different response to an ultrafast optical stimulus than the bulk FM phase. We find that on the sub-ps timescale the T-dependent dynamics mimic the static M(T)-curve, i.e., both ferromagnetic phases seem to contribute to the ultrafast system response. On the 100 ps timescale spin-phonon coupling leads to an additional component in Δ R/R within the bulk FM phase, which is not observed for the high-TC quasi-2D FM phase. An additional signature in the T-dependent relaxation time on a ns timescale around 300 K is tentatively attributed to the vanishing of the 2D FM phase already below its TC,2D due to optical excitation.
Financial support by the DFG within the CRC 1073 is acknowledged.
Ref.: [1] M. Keunecke et al., doi: 10.1002/adfm.201808270