Thermal stability of magnetic characteristics of Co/Ag/Fe and Co/Ag/Fe20Ni80 spin-valve structures

We investigated the thermal stability of magnetic characteristics of Co/Ag/Fe and Co/Ag/Fe20Ni80 spin-valve structures. Thin film systems were obtained with the help of sputtering method. For the first type of systems two particular thicknesses (dML = 3 and 20 nm) and different disposition of magnetic layers (ML) were used. For the second type different thickness of Ag (dNML) spacer layer was used. The research of the crystal structure was performed with the transmission electron microscope. The results demonstrate that every investigated as-deposited sample does not include solid solutions, intermetallic compounds or impurities. It has been found that among the spin-valve structures of the first type the ones with relatively thick Co layer are the most stable. Replacing Fe layer with Fe20Ni80 leads to the improvement in thermal stability of magnetic properties at high temperatures (up to 750 K).