ISSN:
1434-6036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract. The transition from amorphous to polycrystalline microstructure has been studied in sputtered Co x Si1-x alloy films by structural, magneto-optical and Nuclear Magnetic Resonance measurements. For $x \geq 0.76$ , Si is diluted into Co without significantly altering the polycrystalline microstructure, composed of a mixture of hcp and fcc grains. However, the fraction of Co atoms that contribute to the Nuclear Magnetic Resonance signal is found to decrease steeply (down to about 60 $\%$ at x = 0.76) suggesting a microscopic segregation of a Si rich phase that induces a large degree of disorder. This is reflected in a harder magnetic behavior and a strong anisotropy dispersion. Below x = 0.75, the transition to an amorphous microstructure results in a sudden increase in the fraction of Co atoms within a ferromagnetic phase, indicating the recovery of the microscopic homogeneity. Also a significant enhancement of the macroscopic magnetic anisotropy is found for amorphous films with compositions right below the transition. Within the amorphous phase a second regime of Si segregation appears characterized by a constant Co local environment and constant magnetic properties. Finally, for x = 0.65 there is a significant Si enrichment in the Co environment and the films become non magnetic for compositions below this point.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1140/epjb/e2004-00345-0
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