Allgemeines Physikalisches Kolloquium im Wintersemester 2010/2011
Ort:    48149 Münster, Wilhelm-Klemm-Str. 10, IG I, HS 2,
Zeit:    Donnerstag, 05.05.2011 16:00 Uhr c.t.
Kolloquiums-Kaffee ab 15:45 Uhr vor dem Hörsaal

Multichannel Spin Polarimetry and Hard X-ray Photoemission: Breaking old Paradigms

Prof. Dr. G. Schönhense, Institut für Physik, Universität Mainz

Spin-polarization measurements of free electrons remain challenging since their first realization by Mott. As Heisenberg’s uncertainty principle forbids the Stern-Gerlach experiment for free electrons the determination of spin polarization relies on spin-orbit or exchange scattering, reducing the efficiency by orders of magnitude. In turn, important research fields like single shot experiments with XUV laser pulses or non-repetitive phenomena in ferromagnets are inaccessible with state-of-the-art spin detectors. Our novel approach of two-dimensional multichannel spin-detection overcomes this drawback with an efficiency increased by 4 orders of magnitude. With the advent of high-resolution, high-brilliance beamlines for hard X-rays in the 6-10 keV range, photoemission of deeply buried layers and inner interfaces became possible. The mean free path of such fast photoelectrons is of the order of 10 nm, so that probing depths above 20 nm can be reached. When combined with magnetic dichroism and/or spin analysis, this bulk sensitivity provides a powerful tool for the study of magnetic multilayer systems.

Einladender: Prof. Dr. C. Weinheimer

Im Auftrag der Hochschullehrer des Fachbereichs Physik