LAUSR

CoTa alloy thin films were prepared by using magnetron sputtering technique on Si substrates at room temperature. The effect of post-annealing on structural and magnetic properties of CoTa alloy thin films has been investigated in the temperature range of 10–300 K using X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR) and vibrating sample magnetometer (VSM) techniques. It has been observed that the structural and magnetic properties of the prepared films depend on post-annealing. From XRR measurements, the thicknesses of the samples were determined. SEM images indicate the formation of the clusters on the surfaces of CoTa alloy thin film with the post-annealing. The cobalt core peaks indicate the existence of metallic cobalt in the samples. EPR spectra with paramagnetic behaviour appear for both as-grown and annealed CoTa alloy thin films. EPR and VSM measurements have indicated that after the post-annealing, paramagnetic behaviour weakens, ferromagnetic behaviour enhances and effective magnetic anisotropy forms.