Peculiarities of Magnetoresistive Properties of Nanostructured (Ni_{80}Fe_{20})_{x}Au_{1-x} Thin Films: Concentration and Annealing Effects

Abstract

In  this  report,  peculiarities  of  magnetoresistive  properties  of  nanostructured   (Ni₈₀Fe₂₀)_xAu_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 Ni₃Fe 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.