According to the purpose and the current research tasks of complex investigation of crystal structure and phase state, electro- and magnetoresistive properties of nanosized film materials based on permalloy (Py) and Ag, the methods were used: co-evaporation and layered electron-beam condensation in a vacuum; the method of quartz resonator for in-situ measurement of thickness; the methods of transmission electron microscopy, atomic force microscopy, and electronography for investigation of crystal structure and phase state; energy dispersion spectral analysis to determine the composition of the samples; the method of high-precision resistometry in the study of electrophysical and magnetoresistive properties. It was demonstrated that a singled-layer permalloy Ni80Fe20 and Ag thin films before and after annealing up to Тann = 700 К have a single-phase state. It correspond to fcc-Ni3Fe (а = 0.353-0.355 nm) and fcc-Ag (а = 0.407-0.408 nm). It was found that the phase state of nanoscale film materials based on permalloy alloy Ni80Fe20 and Ag after condensation, regardless of the concentration of silver atoms in the system, is a combination of fcc-Ni3Fe + fcc-Ag with an average lattice parameter (fcc-Ni3Fe) а= 0.353 nm and (fcc-Ag) а= 0.407 nm. Temperature treatment of the studied samples at a temperature range Тann = 300-700 К does not change the phase state of the system. The nanoscale system remains two-phase (fcc-Ni3Fe + fcc-Ag with lattice parameters а= 0.356 and 0.408 nm, respectively). On the images of the crystal structure of the samples at сAg = 32-60 at.%, it is possible to distinguish nanosized (L = 2-5 nm) and crystallites with an average size up to 50 nm, which correspond to the ferromagnetic and nonmagnetic components of the system, respectively. In the case of сAg > 70 at.%, the crystalline structure of the film system (Py+Ag)/S can be described as follows: the nanosized grains of the ferromagnetic component is randomly distributed in the volume of the nonmagnetic material. Regularities in concentration and size dependences of resistivity, temperature coefficient of resistance, and temperature of healing of defects for nanosized materials in the range of concentrations сAg = (10-90) ат.% are established. It was demonstrated that the addition of Ag to the permalloy Ni80Fe20 and the increase in the concentration of cAg from 26 to 48 at.% causes an increase in the value of ρ in the system (Py+Ag)/S to 2.5•10 – 7 Оhm•m compared with data for single-layer Ni80Fe20 permalloy films at d = 55nm (ρ(Ру) = 2.0•10 – 7 Оhm•m). A further increase in the concentration of Ag atoms leads to a sharp decrease in the resistivity to the value of , characteristic of a single-layer Ag(55)/S film, which is 1.7•10 – 7 Оhm•m, which is due to changes in the crystal structure of the samples. The concentration dependences of β(cAg) show a minimum at cAg = 48 at.%, which corresponds to the value of β = 1.8•10 3 К-1. It is shown that nanosized film materials (Py+Ag)/S is also characterized by a display of the size effect in thermoresistive properties. The increase in the total thickness from 20 to 100 nm causes a sharp decrease in the value of resistivity 5-6 times, while the value of TCR increases by 2-3 times. The maximum value of the isotropic magnetoresistive effect for freshly condensed samples is 1.85% for samples at cAg = 60 at.% and d = 100 nm and for thermally annealed 1.80% at Тann = 500 K samples cAg = 60 at.% and d = 60 nm (at the measurement at room temperature). Increasing the induction of the applied external magnetic field from 500 mT to 1.5 T does not affect the shape of the field dependence of the magnetic resistance MR(B). Hysteresis and saturation are absent. At the same time, there is an increase in the value of MR to 2.5%. The decrease in the measurement temperature from 300 to 4 K is accompanied by a further increase in the amplitude of the magnetoresistive effect to 3.8%. At the same time, the size dependences of the magnetoresistance for nanoscale film systems (Py+Ag)/S are characterized by the presence of a maximum MR = 1.80% at a thickness of 60 nm and a temperature of 500 K. This maximum is shifted toward smaller thicknesses (d = 50 nm) at the increase in annealing temperature to 700 K and is 0.85%. As-deposited samples are characterized by an increase in MR with increasing thickness with a yield to saturation at d = 100 nm. In the case of forming nanosized materials using the layer-by-layer condensation method, the maximum value of the isotropic MR = 0.35% was obtained in the case of the multilayer system [Py/Ag]16/S, i.e. the system with the maximum number of Py/Ag bilayer repeats. This indicates a greater efficiency of the method of simultaneous condensation for the implementation of isotropic magnetoresistance, greater than 1%.
