Structural and magnetic properties of the Al$_{2}$O$_{3}$/Ge-$p$/Al$_{2}$O$_{3}$/Co system

The Al$_{2}$O$_{3}$/Ge-$p$/Al$_{2}$O$_{3}$/Co system with an Al$_{2}$O$_{3}$ buffer layer deposited by ion-plasma sputtering has been experimentally investigated. The dependences of the magnetic properties of cobalt on the rate of its deposition by ion-plasma sputtering and rate of deposition of preceding layers have been established. It is shown that the technique used to obtain buffer layers can significantly reduce the surface roughness of the next layers. The obtained buffer layers can be used as artificial substrates for growing heterostructures with tunnel junctions.