Spin filtering by proximity effects at hybridized interfaces in spin-valves with 2D graphene barriers
The CNRS-Thales team in Paris and the MODL group at IMCN (UCLouvain) have recently reported on spin transport in epitaxial monolayer graphene based 2D-magnetic tunnel junctions. Spintronic measurements, supported by ab initio calculations, have demonstrated that the strength of interaction between ferromagnetic electrodes and graphene monolayers is found to control the resulting spin signal. In particular, by switching the graphene/ferromagnet interaction, spin transport reveals magneto-resistance signal MR > 80% in junctions with low resistance x area products. Descriptions based only on a simple K-point filtering picture (i.e. MR increase with the number of layers) are not sufficient to predict the behavior of the devices. Indeed, hybridization effects need to be taken into account to fully grasp the spin properties (such as spin dependent density of states) when 2D materials are used as ultimately thin interfaces. While this is only a first demonstration, this research introduce the fruitful potential of spin manipulation by proximity effect at the hybridized 2D material / ferromagnet interface for 2D-magnetic tunnel junctions.
Reference : M. Piquemal-Banci, R. Galceran, S.M.-M. Dubois, V. Zatko, M. Galbiati, F. Godel, M.B. Martin, R.S. Weatherup, F. Petroff, A. Fert, J.-C. Charlier, J. Robertson, S. Hofmann, B. Dlubak, and P. Seneor, Nature Communications 11, 5670 (2020) — Open Access published online on 09 November 2020.