Regensburg 2013 – scientific programme

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MA: Fachverband Magnetismus

MA 45: Magnetic Coupling and Spin Structures

MA 45.1: Talk

Thursday, March 14, 2013, 15:00–15:15, H10

Direct spectroscopic observations of non-rotatable magnetic moments in Fe50Mn50/Co bilayer using XMCD — •Patrick Audehm, Mathias Schmidt, Gisela Schütz, and Eberhard Goering — MPI for Intelligent Systems, formerly MPI for Metals Research, Stuttgart, Germany

The XMCD (X-ray Magnetic Circular Dichroism) is a unique tool for small microscopic magnetic moments, which allows to identify even the smallest fraction of magnetic moments in an element specific way and their separation in spin and orbital contributions. By a double rotation of polarization and magnetization, the dichroic signal is sensitive to non-rotatable magnetic moments. We have performed highly sensitive XMCD studies on a Exchange Bias (EB) system with Fe50Mn50 and Co layer on top. Our transition metal L2,3 edge XMCD analysis of the top (FM) and the underlying FeMn layer (AF) for rotatable magnetic moments provides the pure-metal like spin dominated XMCD spectra. In contrast to this, the non-rotatable moment*s spectra exhibit a nearly pure orbital character. In order to prove this spectacular result, we have verifyed the temperature dependency of this effect, with reduced EB at higher temperature. These experiments point towards the existence of locally loaded spin-orbit-coupling springs on the atomic level. This result is of great importance and has to be considered beyond EB systems as a local source for anisotropy energy in transition metal compounds.