Cobalt/iron multilayers with different layer thickness were electron beam evaporated in ultrahigh vacuum, keeping constant both the number of layers and the Co/Fe thickness ratio. Structural and magnetic properties are thoroughly investigated with different techniques. The multilayers have clean and sharp interfaces. All samples show single-phase magnetic behavior in the temperature range of 5–300 K, due to the strong exchange coupling between the layers. The room temperature hysteresis loops present a sharp switching at a field of ∼8 kA/m, followed by a residual hysteresis extending up to saturation, at fields of several tens of kA/m.

Co/Fe multilayers with different layer thickness formed by electron beam evaporation in ultrahigh vacuum have been investigated by grazing incidence x-ray reflectivity ͑GIXRR͒ and alternating gradient force magnetometry. The interface thicknesses are lower than GIXRR uncertainty ͑ϳ1 nm͒, favoring a strong magnetic exchange interaction between the layers responsible for their single phase magnetic behavior. The hysteresis loops were interpreted as the result of two different magnetization processes related to the presence of an out-of-plane component of the magnetization.

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Co/Fe multilayers were electron-beam evaporated in ultrahigh vacuum onto quartz substrates keeping the Co layer thickness ͑10 nm͒ constant and changing that of Fe ͑10-30 nm͒. For Fe layer thicknesses up to 24 nm, the magnetization substantially lies in the film plane and shows a uniaxial magnetic anisotropy. The coercive field measured along the easy axis is ϳ10 Oe, and the x-ray reflectivity patterns show a superlattice behavior. For a Fe layer thickness equal to 30 nm, the in-plane texture strongly decreases, the coercive field increases up to ϳ100 Oe, the magnetization direction forms an out-of-plane angle of ϳ36°and a stripe magnetic domain structure takes place. The observed in-plane anisotropy and the changing in the magnetic order as a function of the iron layer thickness is discussed and justified, assuming that the growth of the first Co layer occurs by the nucleation of ordered zones, influencing the subsequent layer order via exchange interaction.

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