Testing Epitaxial Co1.5FeGe(001) Electrodes in MgO-based Magnetic Tunnel Junctions

Abstract

The ability of the full Heusler alloy Co1.5Fe1.5Ge(001) (CFG) to be a Half-Metallic Magnetic (HMM) material is investigated. Epitaxial CFG(001) layers were grown by molecular beam epitaxy. The results obtained using electron diffraction, X-ray diffraction, and X-ray magnetic circular dichroism are consistent with the full Heusler structure. The pseudo-gap in the minority spin density of state typical in HMM is examined using spin-resolved photoemission. Interestingly, the spin polarization found to be negative at EF in equimolar CoFe(001) is observed to shift to positive values when inserting Ge in CoFe. However, no pseudo-gap is found at the Fermi level, even if moderate magnetization and low Gilbert damping are observed as expected in HMM materials. Magneto-transport properties in MgO-based magnetic tunnel junctions using CFG electrodes are investigated via spin and symmetry resolved photoemission.

Description
Keywords
Magnetic moments, Germanium, Polarization, Carbon dioxide, Electrodes, Photoemission, Fermi levels, Epitaxy, Magnetic tunnel junctions, Molecular beam epitaxy
Citation
Neggache, A., et al. (2014): Testing Epitaxial Co1.5FeGe(001) Electrodes in MgO-based Magnetic Tunnel Junctions, Applied Physics Letters, 104(25).