Size and Heat Treatment Effects in Magnetoresistive Properties of $(\mathbf{Ni}_{80}\mathbf{Fe}_{20})_{70}\mathbf{Au}_{30}$ Nanostructured Thin-film Materials

The series of (Ni80Fe20)70Au30 thin-film samples within the range of thickness from 10 to 45 nm were prepared by the electron-beam co-evaporation technique with a purpose to investigate the role of the size effect in their magneto resistive properties. The heat treatment effect on magneto resistive properties of investigated systems was discussed also. It was shown that for all samples, the field dependences of magnetoresistance have an isotropic character. It was found that the value of the magnetoresistive effect depend on the thin film thickness and takes a maximum of about 0.43 % at room temperature for sample with a maximum thickness
$d=45$
nm. The variation of field dependences of magneto resistance after annealing has shown that the annealing to 400 and 500 K does not lead to a change in MR value for all investigated samples. The transition to the anisotropic nature of magneto resistance was observed at 600
$\mathbf{K}$
.