Thermal relaxation of the magnetic properties in hard disk recording media

The thermal relaxation of the magnetic properties of thin films for hard disk media is studied. The analyzed magnetic layers are constituted of ternary or quaternary Co-based alloy with different thickness. The relaxation is analyzed with measurements of magnetic viscosity and of coercive field variability. The magnetization switching of the magnetic films is also studied with the rotational hysteresis analysis. The different stability in the films with different compositions and thickness is discussed in relationship with the evolution of the basic processes of magnetization.