Peculiarities of Magnetoresistive Properties of Co/Ag/Py Pseudo Spin Valves Under Heat Treatment

The magnetoresistive properties of pseudo spin valves with the structure Co(5 nm)/Ag(d_Ag)/Py(30 nm)/Sub (Sub-amorphous glass-ceramic substrate) and Co(30 nm)/Ag(d_Ag)/Py(5 nm)/Sub, where Py is permalloy Ni₈₀Fe₂₀, d_Ag = 3–15 nm, was investigated. It is shown that thermal annealing at the temperature of healing defects does not change the structure of both kinds of the investigated pseudo spin valves and improves magnetoresistance. The high-temperature annealing at 750 K leads to the formation disordered solid solution Ag(Co) based on fcc-Ag lattice and affects not only the magnetoresistive curve shape in perpendicular orientation of the magnetic field but also its sign in the case of Co(5)/Ag(d_Ag)/Py(5)/Sub pseudo spin valve. Besides, the coercivity of the samples with d_Ag = 6 nm measured in their plane is the most stable within the annealing process at 750 K.