Low-field current-hysteretic oscillations in spin-transfer nanocontacts

Published

April 19, 2007

Author(s)

Matthew Pufall, William Rippard, Michael Schneider, Stephen E. Russek

Abstract

We have measured spin-transfer-driven, large-amplitude, current-hysteretic, low frequency (less than or equal to} 500 MHz), narrowband oscillations in nanocontacts made to spin valve structures. The oscillations occur in zero field, persist up to 5 mT for in-plane applied fields, and to beyond 400 mT for out-of-plane fields. Unlike previous measurements, here the oscillation frequency is well below that for uniform-mode ferromagnetic resonance, is a weak function of applied field and current, and is highly anharmonic. The oscillations are hysteretic with dc current, appearing at high currents but persisting to lower currents upon decrease of the current. We suggest that these observations are consistent with the dynamics of a nonuniform magnetic state, one nucleated by both the spin-transfer torque and dc current-generated Oersted fields, with dynamics driven by spin transfer. The electrical oscillations are amplitudes and narrowband, with the largest amplitudes on the order of 1 mV and the narrowest linewidths below 1 megahertz.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Pub Type

Journals

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Keywords

magnetics, nanocontact, nanotechnology, oscillator, spin transfer

Citation

Pufall, M. , Rippard, W. , Schneider, M. and Russek, S. (2007), Low-field current-hysteretic oscillations in spin-transfer nanocontacts, Physical Review B (Condensed Matter and Materials Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32577 (Accessed November 21, 2024)