Magnetic and structural characterization of CoFeZr thin films grown by combinatorial sputtering

We report on a detailed investigation of structural and magnetic properties of thin CoFeZr films, produced by combinatorial cosputtering, with compositions in the ranges 30-85 at.% Co, 12-63 at.% Fe, and 4-8 at.% Zr. Extended x-ray absorption fine structure and x-ray diffraction measurements reveal that alloys with a Zr content below 5 at.% are polycrystalline with a bcc structure, while an amorphous morphology is stabilized at Zr contents above 6 at.%. All samples display a growth-induced in-plane uniaxial anisotropy, which is closely related to the Zr concentration gradients across the wafers. A model for the angular dependence of the reduced remanence, including a Gaussian distribution of easy/hard anisotropy axes, is presented and successfully used to fit the data for all samples. The magnetic moments of the polycrystalline films approximately follow the Slater-Pauling curve, and the magnetic moments of the amorphous films follow a similar trend, but with about 20 % lower values. X-ray magnetic circular dichroism measurements show, for the amorphous films, that the Co moments are virtually constant at 1.7(2)mu(B)/atom.