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From molecules to graphene, new opportunities for spintronics beyond conventional materials - Pierre Seneor

CNRS/Thales, Palaiseau & Université de Paris-Sud

LPS – Amphithéâtre moyen

Spintronics is a paradigm focusing on spin as the information vector from quantum information to fast and ultra-low-power non-volatile devices such as the new STT-MRAM memory. Beyond its widely distributed application in data storage it aims at providing more complex architectures for beyond CMOS. Very recently radically novel and exciting opportunities in terms of functionalities and performances for spintronics devices have been opened by molecules and 2D materials. We will show that while graphene has potential for highly efficient spin information transport [1], the molecular structure, the local geometry at the molecule-electrode interface and more importantly the ferromagnetic metal/molecule hybridization can strongly influence interfacial spin properties going from spin polarization enhancement to its sign control in spintronics devices [2]. Originally overlooked opportunities could also lead to develop new spintronics functionalities, unavailable with conventional inorganic materials. Spin dependent transport measurements on ferromagnet/molecules/ferromagnet magnetic tunnel junctions (MTJs) where molecules are organic semiconductors or self-assembled monolayers [3] will be shown highlighting the crucial role of the interface, up to room temperature. In addition we will show that a thin graphene passivation layer can prevent the oxidation of a ferromagnet, enabling its use in novel humide/ambient processes for molecular spintronics. We will show that graphene coating doesn’t spoil the highly surface sensitive spin current polarizer/analyzer behavior, but more importantly adds a new enhanced spin filtering property leading to a new type of 2D-MTJs [4].

[1] B. Dlubak Nature Physics 8, 557 (2012) ; P. Seneor MRS Bulletin 37, 1245 (2012).

[2] C. Barraud Nature Physics 6, 615 (2010) & Phys. Rev. Lett. 114, 206603 (2015) ; M. Galbiati MRS Bulletin 39, 602 (2014).

[3] M. Galbiati, Adv. Mater. 24, 6429 (2012), S. Tatay et al. J. Phys. Cond. Mat 28, 094010 (2016)

[4] MB Martin ACS Nano 8, 7890 (2014) ; B. Dlubak ACS Nano 6, 10930 (2012) ; M. Piquemal-Banci et al J.Phys. D 50, 203002 (2017).


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