Structural, chemical and electronic properties of the Co2MnSi(001)/MgO interface

Abstract

The performance of advanced magnetic tunnel junctions build of ferromagnetic (FM) electrodes and MgO as insulating barrier depends decisively on the properties of the FM/insulator interface. Here, we investigate interface formation between the half-metallic compound Co2MnSi (CMS) and MgO by means of Auger electron spectroscopy, low energy electron diffraction and low energy photoemission. The studies are performed for different annealing temperatures TA and MgO layer coverages (4, 6, 10, 20 and 50 ML). Thin MgO top layers (t_MgO<=10 ML) show distinct surface crystalline distortions, which can only be partly healed out by annealing and furthermore lead to distinct adsorption of carbon species after the MgO surface is exposed to air. For t_MgO> 10 ML the MgO layer surface exhibits clearly improved crystalline structure and hence only marginal amounts of adsorbates. We attribute these findings to MgO misfit dislocations occurring at the interface, inducing further defects throughout the MgO layer for up to at least 10 ML. Furthermore, spin-polarized photoemission spectra of the CMS/MgO interface are obtained for MgO coverages up to 20 ML, showing a clear positive spin polarization near the Fermi energy in all cases.

To be submitted to Physical Review B

References in corpus (4)

• Epitaxial film growth and magnetic properties of Co_2FeSi
• Thermodynamics of the Heusler alloy Co_2-xMn_1+xSi: a combined density functional theory and cluster expansion study
• Electron correlations in Co${}_2$Mn${}_{1-x}$Fe${}_x$Si Heusler compounds
• Surface spin polarization of the non-stoichiometric Heusler compound Co2Mn(alpha)Si

Cited by in corpus (6)

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• Visualizing half-metallic bulk band structure with multiple Weyl cones of the Heusler ferromagnet
• Monitoring surface resonances on Co2MnSi(100) by spin-resolved photoelectron spectroscopy
• Band structure tuning of Heusler compounds revisited: Spin- and momentum-resolved electronic structure analysis of compounds with different band filling
• Surface resonance of the Heusler half metal Co2MnSi probed by SX-ARPES
• Spin Dependent Lifetimes and Spin-orbit Hybridization Points in Heusler Compounds