Structural and magnetic characteristics of nanogranular Co–Al$_{2}$O$_{3}$ single- and multilayer films formed by the solid-state synthesis

The results of structural and magnetic investigations of nanogranular Co–Al$_{2}$O$_{3}$ films formed from Co$_3$O$_4$/Al thin-film layered structures upon vacuum annealing are reported. The Co$_3$O$_4$/Al films have been obtained by sequential reactive magnetron sputtering of a metallic cobalt target in a medium consisting of the Ar+O$_{2}$ gas mixture and magnetron sputtering of an aluminum target in the pure argon atmosphere. It is shown that such a technique makes it possible to obtain nanogranular Co–Al$_{2}$O$_{3}$ single- and multilayer thin films with a well-controlled size of magnetic grains and their distribution over the film thickness.