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Lowest energy loss in an ultrathin ferromagnetic film William Bailey, Columbia University, DMR-0239724.
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Lowest energy loss in an ultrathin ferromagnetic film William Bailey, Columbia University, DMR-0239724 Ferromagnetic metals lose energy as their magnetic moments change direction. The minimum rate of energy loss is given by the Gilbert relaxation rate G, a constant for a given metal. For the last 50 years, G has been known to be lowest in Fe, with G=57 MHz. We have created an epitaxial alloy thin film, MgO/Fe0.73V0.27(8nm), with substantially reduced loss rate of G=35 MHz. Left: Ferromagnetic resonance (FMR) linewidth as a function of radio frequency; G is proportional to slope. Bottom: Frequency linewidth f; V-alloy has reduced f. C. Scheck, L. Cheng, I. Barsukov, Z. Frait, and W. E. Bailey, Phys. Rev. Lett.98, 117601* (2007) * Editors' Suggestion
Role of energy loss (damping) in Ghz magnetic devices W. Bailey, Columbia University, DMR-0239724 CPP read head Suppress mag-noise: low G Integrated, frequency-agile GHz notch filter (low G: high Q) Suppress SMT-noise: high G N. Smith, APL SMT-switched M-RAM Spin momentum transfer (critical current ~ G) Slonczewski, JMMM low G