Contemporary technological progress is achieving new results due to current needs in microelectronics, superconductivity and nanotechnology. An important feature of high-speed, low-power microelectronics is the spin valve, which is made up of superconducting nanoscale layers such as niobium and cobalt. These two orders superconductivity and ferromagnetism, which at first sight have diametrically opposite tangents and in the natural state are virtually never next to each other - due to the Larkin - Ovchinnikov - Fulde - Ferrell (LOFF) state, demonstrate quantum phenomena quite exciting for further development with applications in: computer technology, chemistry, biology, pharmacology, artificial intellect etc. In this context of ideas we present research on Nb/Co hybrid structures with superconducting properties and the determination of the critical thickness of the superconducting Nb layer in contact with Co.