Showing papers by "Florian Godel published in 2015"
TL;DR: In this article, it was shown that an external large out-of-plane electric field (in the order of 0.5 GV/m) favors in-plane magnetization orientation, due to an electric-field-induced magnetic anisotropy along the normal to the plane.
Abstract: Magnetic properties of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ epitaxial clusters inserted in an Fe/MgO/Fe tunnel barrier are revealed by their tunnel magnetoresistance signature. The cluster assembly has been shown in a previous work to behave as a superparamagnet when a magnetic field was applied in the plane of the tunnel junction. We here demonstrate that an external large out-of plane electric field (in the order of 0.5 GV/m) favors in-plane magnetization orientation. This is due to an electric-field-induced magnetic anisotropy along the normal to the plane, corresponding to large anisotropy fields reaching up to 2 T. The assembly of clusters is thus strictly speaking not superparamagnetic and its magnetization cannot be exactly described by a Langevin law. This is attributed either to a strain-induced enhanced magnetoelectric effect or to a voltage-induced change of the magnetic anisotropy at interfaces with MgO.
9 citations
Dissertation•
08 Dec 2015
TL;DR: In this paper, a barriere tunnel of MgO/Gr/Ni was constructed by using a modele de canaux de conduction assistes par phonons, with the aim of detecting spin.
Abstract: Mes travaux de these portent sur la fabrication et la caracterisation electrique et magnetique de jonctions tunnel a base de graphene. C’est autour de l’idee d’apporter une meilleur comprehension des mecanismes d’injection et de detection d’un courant de charge et de spin aux interfaces graphene/ferromagnetique que s’articule ce manuscrit. Apres avoir demontre qu’il est possible de faire croitre de maniere epitaxiee une barriere tunnel de MgO sur graphene, nous avons etudie les mecanismes de transport dependant en spin dans des jonctions verticales de Co/MgO/Gr/Ni. Nous avons mis en evidence l’interaction du graphene avec l’electrode de nickel a travers les inversions de signe de la magnetoresistance. Celles-ci peuvent etre expliquees a l’aide d’un modele de canaux de conduction assistes par phonons. Enfin du blocage de Coulomb reproductible a ete mesure dans des amas d’aluminium potentiellement mono disperses et auto assembles sur graphene.