P2

Thin films of new materials with high spin polarization (Jakob)

Thin films of Heusler compounds have displayed great potential for magnetoelectronics. Nevertheless, there is no consensus as to what actual/specific compound is ideally suited and as to what are the best processing parameters for an existing material. We will continue our successful growth of new Heusler-type thin films by cathode sputtering and laser ablation. The aim is to deposit well ordered films of a Heusler material where the Fermi energy is in the centre of a wide spin minority band gap, as this will be the decisive parameter for room temperature applications According to band structure calculations, the material systems Co₂Mn_1-xFe_1-xSi and Co₂FeAl_1-xSi_x are promising candidates, while other materials will also be explored in cooperation with Projects P 1 (Felser) and P 7 (Schönhense/Felser). The purity of the deposition environment will be further enhanced. Analytical investigations will be performed in other projects such as Projects P 5 (Elmers), P 10 (Cinchetti/Aeschlimann), and P 9 (Hamrle/Hillebrands). If necessary, we can transfer samples under UHV conditions by using a demountable sample chamber. In this project, we will perform detailed transport measurements to determine the degree of atomic disorder, to establish the anisotropic magnetotransport properties of Heusler materials, and to relate these properties to the spinorbit coupling effects.