Nanostructured hybrids of ferromagnets (FM) and diluted magnetic semiconductors (DMS) will be developed and investigated by means of time- and spatially resolved magneto-optical spectroscopy. The convincing experimental observation of the impact of the magnetic fringe field on the magnetization and the magneto-optical properties of the underlying semiconductor on a Sub-micron scale during the first project period put us now in a position to mainly con-centrate on the dynamical properties of the hybrid nanostructures.

From the technological point of view two challenges have to be solved. To increase the me-chanical stability, the DMS will be grown on transparent ZnSe substrates. For obtaining a re-manent out-of-plane magnetization we intend to use shape-engineering in FM nanostructures with a large saturation magnetization (Dy, Co) and nanostructured multilayers (Fe/Ge, Co/Pt), where the magnetization orientation can be adjusted by the layer sequence, respectively.

The main focus of research will be the dynamical properties of the hybrids. This includes eluci-dating the magnetization as well as the (carrier) spin dynamics in the DMS and the magnetiza-tion dynamics of the FM, respectively, by polarization and time-resolved magneto-optics. As a main goal during this project period we want to demonstrate the dynamical coupling of the nanostructured FM to the underyling DMS. For that purpose, FM nanostructures with a rema-nent magnetization close to the out-of-plane in-plane transition will be designed. A modula-tion of the FM magnetization will be induced by an intense pump pulse and probed by the dy-namical response of the magneto-optical properties of the underlying DMS.

H. Schömig and A. Forchel, S. Halm and G. Bacher, W. Kipferl and C. H. Back, J. Puls and F. Henneberger: Micromagnetoluminescence on Ferromagnetic-Semiconductor Hybrid Nanostructures. J. Appl. Phys. 95, 7411 (2004)

H. Schömig and A. Forchel, S. Halm and G. Bacher, J. Puls and F. Henneberger: Magnetic imprinting of submicron ferromagnetic wires on a diluted magnetic semiconductor quantum well . Appl. Phys. Letters 84, 2826 (2004)

A. Hundt, J. Puls, A. V. Akimov, Y. H. Fan, and F. Henneberger: Photocarrier-induced spin heating and spin-lattice relaxation in diluted magnetic Stranski-Krastanov quantum dots. Phys. Rev. B 72, 033304 (2005)

S. Halm, F. Seifert, T. Kümmell, E. Schuster, W. Keune, J. Puls, F. Henneberger, and G. Bacher: Ferromagnetic spin trapping in a semiconductor. submitted to Nature