Fabrication of perpendicularly magnetized magnetic tunnel junctions with L10-CoPt/Co2MnSi hybrid electrode

Magnetic tunnel junctions (MTJs) of perpendicularly magnetized L10-CoPt/Co2MnSi/MgO/FePt structure were fabricated. In-plane x-ray diffraction measurements and element specific evaluation of magnetic properties using soft x-ray magnetic circular dichroism were carried out to examine quite thin Co2MnSi (CMS) inserted layer between CoPt and MgO interface. Ordered B2-CMS was successfully fabricated onto L10-CoPt as thin as 1 nm thick, and CMS layer shows perpendicular magnetic anisotropy below 3 nm thick via exchange coupling with CoPt layer. In the MTJ-stacking, epitaxial growth was confirmed except for partial misalignment in the upper FePt layer, and coercive field difference clearly appeared between the bottom and the top ferromagnetic electrodes.