Magnetic and structural properties of amorphous CoTi soft ferromagnetic thin films. II. Structural properties

The structure of amorphous ${\mathrm{Co}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Ti}}_{\mathrm{x}}$ thin films prepared by rf sputtering was studied by electron microscopy as a function of the deposition parameters and the concentration of the layers. We tried to simulate the experimental diffraction spectra by a structural model which took into account the short-range order observed in the corresponding crystalline alloy. The model which gave the best agreement with the experimental results is a random continuous network built up of clusters with trigonal, octahedral, and icosahedral symmetry. The size and the structural correlations between the various clusters were also determined. By changing the respective amount of the clusters we could simulate the slight variations of the characteristics of the diffused intensities obtained on samples deposited under a different pressure of the sputtering gas $P_{\mathrm{Ar}}$. This structural model provided an explanation of the variations of the induced anisotropy $K_u$ with $P_{\mathrm{Ar}}$ with thermomagnetic annealing, and as a function of the concentration of the films. These results are reported in paper I.