Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.73: Poster

Freitag, 29. Februar 2008, 11:15–14:00, Poster E

Investigation of multiferroics with ultrafast nonlinear optics — •Tim Günter¹, Tim Hoffmann¹, Takuya Satoh², Thomas Lottermoser¹, and Manfred Fiebig¹ — ¹HISKP, Universität Bonn, Germany — ²Institute of Industrial Science, University of Tokyo, Japan

The dynamic properties of multiferroics and thin multiferroic films (except BiFeO₃) have been rarely studied so far. Here, a femtosecond laser setup is introduced that allows us to investigate both aspects. High time resolution is required for the investigation of dynamical properties and high peak intensities are needed for obtaining detectable SHG signal from thin films. In our fs-laser setup we use an amplified 130 fs Ti:Sapphire laser with 2,5 mJ pulse energy for operating two independent workplaces. Each branch is supplied with an optical parametric amplifier covering a wavelength range from 520 nm to 2600 nm. In the first branch, we use a pump-and-probe setup where optical second harmonic generation (SHG) is employed as probe process because many multiferroics are antiferromagnetic. Delays of up to 12 ns are set by use of a four-pass delay line. By setting different polarization configurations for each delay time, both the amplitude and the phase of the SHG signal are determined with high accuracy. In the second branch, the domain topography of thin multiferroic films is investigated. For this purpose, a transmission and reflection SHG setup with a CCD camera as detector is used. First experiments on the magnetization dynamics of magnetoelectric Cr₂O₃ and the magnetic properties of multiferroic HoMnO₃ films are reported.