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Spin - Orbit driven phenomena in magnetic nanostructures

Mardi 26 juin 2018 11:00 - Duree : 1 heure
Lieu : Salle « Remy Lemaire » (K223) de l’Institut Néel – au n°25 de la rue des martyrs, Grenoble.

Orateur : Julio CAMARERO (Universidad Autonoma de Madrid and IMDEA Nanosciences)

The development of magnetic devices exploiting Spin Orbit effects at room temperature is at the forefront of actual nanomagnetism research. Here, I will first introduce an instrument able to measure simultaneously magnetic and transport properties at any angle, in any kind of magnetic nanostructure, which provides the experimental evidence of the direct link between them [1]. This is a crucial towards the understanding and the improvement of their functionalities. In particular, I will focus how to induce a sizeable and switchable large anisotropic magnetoresistance (AMR) in perovskite half-metallic systems at room temperature by nanoscale engineering of the film surface/interface [2]. In these compounds, transport is coupled to magnetism by a double exchange mechanism and by the spin-polarized nature of conduction electrons. Harnessing the magnetotransport responses is essential for device design and operation, and in particular, to exploit the potentiality of these compounds to sense extremely low current density envisaging their use in artificial neural interfaces [3]. In the second part of the talk, I will report on high quality, graphene/Co(111)/Pt(111) stacks grown epitaxially on (111)-oriented oxide crystals that exhibit enhanced perpendicular magnetic anisotropy (PMA) for Co layers up to 4 nm thick and left-handed Néel-type chiral domain walls (DWs) stabilized by interfacial Dzyaloshinskii–Moriya interaction (DMI). Interestingly, such DMI is localized at both graphene/Co and Co/Pt interfaces and with opposite sign [4,5]. In particular, while the DMI at Co/Pt side is due to the intrinsic SOC, the sizeable DMI experimentally found at the gr/Co interface has Rashba origin. The resulting active magnetic texture is protected by the graphene monolayer and stable at 300 K in air, and, since it is grown on an insulating substrate, be able to transport measurements [6].

[1] P. Perna, et al, Direct experimental determination of the anisotropic magnetoresistive effects ; Appl. Phys. Lett. 104, 202407 (2014) ; Phys Rev B 92, 220422(R) (2015)

[2] P. Perna, et al., Engineering Large Anisotropic Magnetoresistance in La0.7Sr0.3MnO3 Films at Room Temperature, Adv. Funct. Mater. 1700664 (2017).

[3] ByAXON, Towards an active bypass for neural reconnection. H2020-FETOPEN-2016-2017 no 737116

[4] F. Ajejas, et al., Unraveling Dzyaloshinskii–Moriya interaction and chiral nature of Graphene/Cobalt interface, preprint at https://arxiv.org/abs/1803.07443 (2018).

[5] F. Ajejas, et al., Tuning domain wall velocity with Dzyaloshinskii-Moriya interaction, Appl. Phys. Lett. 111, 202402 (2017).

[6] SOgraphene, Tailoring Spin-Orbit Effects in Graphene for Spin-Orbitronic Applications. FLAG ERA Graphene Flagship. PCIN-2015-126.

Contact : jan.vogel@neel.cnrs.fr

Discipline évènement : (Physique)
Entité organisatrice : (Institut Néel)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire nanomagnétisme et spintronique)
Site de l'évènement : Polygone scientifique

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