Ferromagnetic resonance in tunnel junctions: Mag-noise and complex impedance analysis
Autor: | J. R. Childress, Valeri Synogatch, Neil Smith |
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Rok vydání: | 2003 |
Předmět: | |
Zdroj: | Journal of Applied Physics. 93:8570-8572 |
ISSN: | 1089-7550 0021-8979 |
DOI: | 10.1063/1.1557852 |
Popis: | Ferromagnetic resonance (FMR) in the Co80Fe20/Ni80Fe20 free (sense) layer of micron-sized, magnetic tunnel junction (MTJ) devices is studied by two different techniques. The first method employs the MTJ device’s magnetoresistance, and measures thermally excited magnetization fluctuations (mag-noise) as a resistance noise spectrum. Correlations between magnetoresistance and FMR frequency versus in-plane magnetic field have been observed for different devices. The FMR frequencies agreed well with calculations when including substantial out-of-plane magnetic anisotropy fields. The second method detects the change in the complex impedance of the MTJ before and after applying a dc current, as measured by a vector network analyzer. The latter method seems to be very sensitive to internal nonuniform states of the free layer magnetization. |
Databáze: | OpenAIRE |
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