Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)
MA 40.63: Poster
Freitag, 27. März 2009, 11:00–14:00, P1A
Propagating and standing acoustic waves in Oxide multilayers — •Marc Herzog1, Mareike Kiel1,2, Ionela Vrejoiu3, Marin Alexe3, Dietrich Hesse3, and Matias Bargheer1,2 — 1Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam-Golm, Germany — 2Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14476 Potsdam-Golm, Germany — 3Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
We investigate the ultrafast optical response of oxide multilayers composed of ferromagnetic metals (SrRuO3 = SRO and (La,Sr)MnO3 = LSMO), ferroelectrics (Pb(Zr,Ti)O3 = PZT and BaTiO3 = BTO) and the dielectrics (SrTiO3 = STO). Typically 10 double layers (superlattice) of approx. 10 nm thickness are sufficient to define a mini-Brillouin zone, giving rise to the zone-folding of phonons and phonon band gaps. A tunable femtosecond pulse (IR, vis or UV) excites coherent phonons (strain waves) with the wavevector given by the artificial periodicity. An ultrashort whitelight continuum probes the transient reflectivity and transmission. The spectral and temporal information is used to disentangle standing and propagating strain waves and, moreover, to understand the fundamental processes driving the strain waves, such as electron-phonon coupling. In particular, we study the temperature dependence of the ultrafast response when tuning through ferroelectric and ferromagnetic phase transitions. These studies may be relevant for devices exploiting the coupled dynamics of several functional nanolayers.