Spin transfer precessional dynamics in Co60Fe20B20 nanocontacts

We report on the precessional dynamics in spin transfer oscillators having Co60Fe20B20 free layers as a function of annealing time at 225°C. Repeated annealing reduces the critical current Ic by roughly a factor of 3 and increases the tunability of the oscillation frequency with current df∕dI. The d...

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Bibliographic Details
Published in:Journal of applied physics 2008-03, Vol.103 (5)
Main Authors: Rippard, W. H., Pufall, M. R., Schneider, M. L., Garello, K., Russek, S. E.
Format: Article
Language:English
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Summary:We report on the precessional dynamics in spin transfer oscillators having Co60Fe20B20 free layers as a function of annealing time at 225°C. Repeated annealing reduces the critical current Ic by roughly a factor of 3 and increases the tunability of the oscillation frequency with current df∕dI. The decrease in Ic correlates with an increasing giant magnetoresistance (GMR) during the first 3h of annealing. For longer times, df∕dI continues to increase, although the GMR does not. The variations in the macroscopic Co60Fe20B20 magnetization parameters and contact dimensions with annealing are not sufficient to account for the later changes.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.2838490