The Effect of the Transition from Layered to Granular Structures on the Magnetoresistive Properties in the Systems Based on Fe_xNi_100−x and Cu

Abstract

The conducted electron diffraction and electron microscopy studies have shown that the phase state of as-deposited and annealed at 700 K three-layer film systems based on ferromagnetic alloy Fe_xNi_100−x (F-layer) and Cu (N-layer) (x > 60 wt%, d_F = 10–40 nm, d_N = 2–20 nm) corresponds to BCC-(Fe–Ni) + FCC-Cu. The study of diffusion processes by the SIMS method showed that the individuality of the layers after annealing at a temperature of 700 K is retained only for systems with relatively thick layers (d_F = 30–40 nm, d_N = 5–20 nm). After thermostabilization of film systems with d_F = 10–20 nm, d_N = 5–20 nm at 700 K, a granular state is observed. It is shown that spin-dependent scattering of electrons is carried out in as-deposited samples. Annealing at temperatures of 400–500 K leads to a significant decrease in the isotropic magnetoresistance magnitude. Further increase the annealing temperature up to 700 K causes the growth of the isotropic magnetoresistance due to the formation of a granular state.