Electrophysical Properties of [Ni80Fe20/SiOx)]n Discontinuous Multilayers

In this research, [Ni80Fe20(d)/SiOx(5)]5/S discontinuous multilayers were fabricated using the method of layer-by-layer electron-beam evaporation. The phase composition, structural features, and electrophysical properties of the samples were investigated depending on the effective thickness of the ferromagnetic Ni80Fe20 layers and annealing temperature. Based on transmission electron microscopy and electron diffraction analysis, it was established that the samples exhibit a nanocrystalline structure of Ni80Fe20 grains embedded in an amorphous SiOx matrix, with a phase composition corresponding to fcc-Ni3Fe, which remains stable after annealing at 500 and 700 K. The average grain size of Ni80Fe20 increases with thickness and annealing temperature, contributing to changes in transport properties. The temperature dependences of resistivity and the temperature coefficient of resistance (TCR) were studied within several heating/cooling cycles up to 600 K. It was found that for structures with Ni80Fe20 thickness d = 4 – 8 nm, a metallic conduction regime is realized, characterized by positive TCR values. In contrast, structures with d = 3 nm demonstrate nearly constant resistivity with temperature and TCR values close to zero, indicating a transition conduction regime where metallic and tunneling mechanisms coexist. The annealing process leads to a reduction in resistivity due to structural ordering. The results confirm that both resistivity and TCR are monotonic functions of Ni80Fe20 layer thickness, which is associated with changes in grain size and intergranular distances. These findings are essential for tailoring the transport behavior of magnetic discontinuous multilayers for future applications in spintronics, sensors, and functional nanomaterials.