Magnetic nano-oscillator driven by pure spin current

• Published in: Nature materials Vol. 11; no. 12; pp. 1028 - 1031
• Main Authors: Demidov, Vladislav E., Urazhdin, Sergei, Ulrichs, Henning, Tiberkevich, Vasyl, Slavin, Andrei, Baither, Dietmar, Schmitz, Guido, Demokritov, Sergej O.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-12-2012; Nature Publishing Group
• Subjects: 639/301/119/1001; 639/925/927/1062; Biomaterials; Coherence; Condensed Matter Physics; Devices; Dynamics; Electrical engineering; Electronics; Fluctuations; Injection; letter; Materials Science; Microwaves; Nanocomposites; Nanomaterials; Nanostructure; Nanostructured materials; Nanotechnology; Optical and Electronic Materials; Oscillators; Spintronics
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat3459

The dynamical processes associated with the magnetization of a material can be drastically altered by the application of a spin current. This study now demonstrates the feasibility of selectively exciting coherent auto-oscillation modes in magnetic nanostructures.
With the advent of pure-spin-current sources, spin-based electronic (spintronic) devices no longer require electrical charge transfer, opening new possibilities for both conducting and insulating spintronic systems
1
,
2
,
3
,
4
,
5
,
6
,
7
,
8
,
9
. Pure spin currents have been used to suppress noise caused by thermal fluctuations in magnetic nanodevices, amplify propagating magnetization waves, and to reduce the dynamic damping in magnetic films
10
,
11
,
12
,
13
,
14
. However, generation of coherent auto-oscillations by pure spin currents has not been achieved so far. Here we demonstrate the generation of single-mode coherent auto-oscillations in a device that combines local injection of a pure spin current with enhanced spin-wave radiation losses. Counterintuitively, radiation losses enable excitation of auto-oscillation, suppressing the nonlinear processes that prevent auto-oscillation by redistributing the energy between different modes
12
,
15
. Our devices exhibit auto-oscillations at moderate current densities, at a microwave frequency tunable over a wide range. These findings suggest a new route for the implementation of nanoscale microwave sources for next-generation integrated electronics.