Increase of magnetic damping in thin polycrystalline Fe films induced by Cu/Fe overlayers
| Autor: | Shu Fan Cheng, Peter Lubitz, F. J. Rachford |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 93:8283-8285 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.1557340 |
| Popis: | The ferromagnetic resonance properties of thin polycrystalline layers in the sequence Cu/Fe/Cu/Fe/Cu, grown on Si wafers, were studied. Fe grown on Cu can have a very narrow ferromagnetic resonance (FMR) linewidth. Similar structures are of interest for spin transport studies and for giant magnetoresonance applications. The thinner Fe underlayer ranged from 2 to 5 nm, the intermediate Cu spacer thickness from 2 to 10 nm, and the Fe outer layer was 20 nm thick. The increased damping of the thinner Fe layer in this structure, as reflected in the FMR linewidths observed at 9.46 and 33.5 GHz, is similar to that predicted by Berger and recently observed experimentally using epitaxial single crystal Fe films. In addition to confirming the 1/(Fe layer thickness) dependence of the additional damping, the present measurements show a decrease of damping with increasing Cu spacer thickness, implying a short spin transport decay length in our Cu of about 3.5 nm. The linewidth in isolated Cu/Fe/Cu layers also increased with decreasing Fe thickness, as predicted and observed in some other cases. Magnetization data indicate negligible magnetic coupling of the Fe layers except for the smallest interlayer Cu thicknesses used. The linewidths studied increased moderately with cooling to 77 K. The ferromagnetic resonance properties of thin polycrystalline layers in the sequence Cu/Fe/Cu/Fe/Cu, grown on Si wafers, were studied. Fe grown on Cu can have a very narrow ferromagnetic resonance (FMR) linewidth. Similar structures are of interest for spin transport studies and for giant magnetoresonance applications. The thinner Fe underlayer ranged from 2 to 5 nm, the intermediate Cu spacer thickness from 2 to 10 nm, and the Fe outer layer was 20 nm thick. The increased damping of the thinner Fe layer in this structure, as reflected in the FMR linewidths observed at 9.46 and 33.5 GHz, is similar to that predicted by Berger and recently observed experimentally using epitaxial single crystal Fe films. In addition to confirming the 1/(Fe layer thickness) dependence of the additional damping, the present measurements show a decrease of damping with increasing Cu spacer thickness, implying a short spin transport decay length in our Cu of about 3.5 nm. The linewidth in isolated Cu/Fe/Cu layers also increase... |
| Databáze: | OpenAIRE |
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