Issue
EPL
Volume 87, Number 5, September 2009
Article Number 57001
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/87/57001
Published online 16 September 2009
EPL, 87 (2009) 57001
DOI: 10.1209/0295-5075/87/57001

Auto-oscillation threshold and line narrowing in MgO-based spin-torque oscillators

S. Cornelissen1, L. Bianchini2, 3, G. Hrkac4, M. Op de Beeck1, L. Lagae1, Joo-Von Kim2, 3, T. Devolder2, 3, P. Crozat2, 3, C. Chappert2, 3 and T. Schrefl4

1   IMEC - Kapeldreef 75, B-3001 Leuven, Belgium, EU
2   Institut d'Electronique Fondamentale, CNRS, UMR 8622 - 91405 Orsay, France, EU
3   Université Paris-Sud - 91405 Orsay, France, EU
4   Department of Engineering Materials, University of Sheffield - Sheffield S1 4DU, UK, EU

joo-von.kim@u-psud.fr

received 4 May 2009; accepted in final form 17 August 2009; published September 2009
published online 16 September 2009

Abstract
We present an experimental study of the power spectrum of current-driven magnetization oscillations in MgO tunnel junctions under low bias. We find the existence of narrow spectral lines, down to 8 MHz in width at a frequency of 10.7 GHz, for small applied fields with clear evidence of an auto-oscillation threshold. Micromagnetics simulations indicate that the excited mode corresponds to an edge mode of the synthetic antiferromagnet.

PACS
75.75.+a - Magnetic properties of nanostructures.
72.25.Pn - Current-driven spin pumping.
85.75.-d - Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields.

© EPLA 2009