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Agility of vortex-based nanocontact spin torque oscillators

2009; American Institute of Physics; Volume: 95; Issue: 19 Linguagem: Inglês

10.1063/1.3263727

1520-8842

Mauricio Manfrini, T. Devolder, Joo-Von Kim, P. Crozat, N. Zerounian, C. Chappert, W. Van Roy, Liesbet Lagae, G. Hrkac, T. Schrefl,

Physics of Superconductivity and Magnetism

We study the agility of current-tunable oscillators based on a magnetic vortex orbiting around a point contact in spin-valves. Theory predicts frequency-tuning by currents occurs at constant orbital radius, so an exceptional agility is anticipated. To test this, we have inserted an oscillator in a microwave interferometer to apply abrupt current variations while time resolving its emission. Using frequency shift keying, we show that the oscillator can switch between two stabilized frequencies differing by 25% in less than ten periods. With a wide frequency tunability and a good agility, such oscillators possess desirable figures of merit for modulation-based rf applications.