Dresden 2006 – scientific programme

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MA: Magnetismus

MA 30: Spin-Electronics II

MA 30.4: Talk

Thursday, March 30, 2006, 16:00–16:15, HSZ 103

Tunnel junctions with the Heusler-electrode Co₂Cr_0.6Fe_0.4Al — •Martin Jourdan, Andres Conca, Christian Herbort, Anna Gerken, and Hermann Adrian — Institut für Physik, Johannes Gutenberg Universität, 55099 Mainz, Germany

Due to the theoretically predicted half-metallicity of the Heusler compound Co₂Cr_0.6Fe_0.4Al tunneling junctions employing this material as electrodes promise huge magnetoresistance effects. However, the control and understanding of the influence of the interface and tunneling barrier properties on the tunneling magnetoresistance (TMR) poses a challenge.
Recently we were able to prepare well ordered (B2 structure) epitaxial thin films of Co₂Cr_0.6Fe_0.4Al which serve as a base electrode of Co₂Cr_0.6Fe_0.4Al-AlO_x-Co-CoO junctions. The dependence of the TMR-effect on the deposition temperature of the Heusler-electrode and the parameters of barrier preparation is presented. The electrode-barrier interface is characterized by in situ STM and RHEED as well as TEM. The relation between the bulk properties of the Co₂Cr_0.6Fe_0.4Al electrode and the tunneling magnetoresistance of the junctions is investigated.