Microwave signal emission in spin-torque vortex oscillators in metallic nanowires: Experimental measurements and micromagnetic numerical study

F. Abreu Araujo, M. Darques, K. A. Zvezdin, A. V. Khvalkovskiy, N. Locatelli, K. Bouzehouane, V. Cros, and L. Piraux

Phys. Rev. B 86, 064424 – Published 17 August 2012

Abstract

We report on microwave oscillations induced by spin-transfer torque in metallic spin valves obtained by electrodeposition of Co-Cu-Co trilayer structures in nanoporous alumina templates. Using micromagnetic calculations performed on similar spin-valve structures it was possible to identify the magnetization dynamics associated with the experimentally determined microwave emission. Furthermore it appears that in our particular geometry the microwave emission is generated by the vortex gyrotropic motion which occurs in, at least, one of the two magnetic layers of our spin-valve structures. Microwave emission was obtained in the absence of any external magnetic field with the appropriate magnetization configuration.

Received 27 March 2012

DOI:https://doi.org/10.1103/PhysRevB.86.064424

Authors & Affiliations

F. Abreu Araujo^1,*, M. Darques^1,†, K. A. Zvezdin^2,3, A. V. Khvalkovskiy^2,4,‡, N. Locatelli⁴, K. Bouzehouane⁴, V. Cros⁴, and L. Piraux¹

¹Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Croix du Sud 1, BE-1348 Louvain-la-Neuve, Belgium
²A. M. Prokhorov General Physics Institute, RAS, Vavilova, 38, 119991 Moscow, Russia
³Istituto P.M. srl, Via Grassi 4, I-Torino, Italy
⁴Unité Mixte de Physique CNRS/Thales, 1 Ave A. Fresnel, 91767 Palaiseau, and Université Paris-Sud, F-91405 Orsay, France

^*Author to whom correspondence should be addressed: flavio.abreuaraujo@uclouvain.be (Flavio Abreu Araujo)
^†Now at LTM-CNRS/CEA-LETI, 17 rue des martyrs, 38000 Grenoble, France.
^‡Now at Grandis, inc., 1123 Cadillac Court, Milpitas, CA 95035, USA.

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Vol. 86, Iss. 6 — 1 August 2012

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