Peculiarities of Magnetoresistive Properties of Nanostructured (Ni80 Fe20)xAu1-x Thin Films: Concentration and Annealing Effects

Abstract

In this report, peculiarities of magnetoresistive properties of nanostructured (Ni 80 Fe 20 ) x Au 1 − x thin films containing from 10 to 60 at.% of Au were investigated. We focus on the samples with a thickness of 45 nm fabricated by the method of electron-beam co-evaporation. The influence of Au atoms concentration and the annealing process within the temperature range from 300 to 700 K on the microstructure, magnitude, and nature of magnetoresistive effects has been discussed. The analysis of electronographic studies showed that both face-centered cubic Ni 3 Fe and Au phases are visible in the diffraction images. Upon varying thin film compositions and annealing conditions, the phase state does not change. At the same time, magnetoresistive properties of thin films demonstrated a strong dependence on both the concentration of sample components and annealing conditions. Samples after deposition showed typical giant magnetoresistance behavior at 20–46 at.% of Au, which is also typical for samples annealed at 400 and 500 K. The transition to the anisotropic nature of magnetoresistance occurs upon annealing at 500 K.