Dresden 2006 – scientific programme

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MA: Magnetismus

MA 30: Spin-Electronics II

MA 30.1: Talk

Thursday, March 30, 2006, 15:15–15:30, HSZ 103

Spin-resolved photoemission studies at the Fe(001)/MgO interface — •Martina Müller, Frank Matthes, and Claus M. Schneider — Institut für Festkörperforschung, Forschungszentrum Jülich

The epitaxial system Fe(001)/MgO/Fe represents one of the most interesting materials for studying the tunnel magnetoresistance effect (TMR). In order to explain discrepancies between experimental results and theoretical predictions for the height of TMR, our experiments focus on the properties of the interface between Fe(001)/MgO since its electronic structure strongly determines the interfacial coupling. We performed spin-resolved photoemission experiments at the Synchrotron DELTA (Dortmund) studying the Fe (3d) valence bands covered with an ultrathin MgO layer. The samples were produced by molecular beam epitaxy and characterized in-situ by Auger spectroscopy and low energy electron diffraction. The systematic variation of either oxidation and layer thickness of the on-top MgO covering reveals different processes: A spin dependent attenuation of the Fe (3d) minority channel is observed for varying MgO thickness whereas electrons of both spin directions are involved in the change of electronic structure when passing from an oxidic to a more metallic MgO capping layer. The analysis of the Fe spin polarization completes the investigations by uncovering the spin dependent bonding conditions at the Fe(001)/MgO interface.