Effect of insulator matrix on electrical transport properties of iron-insulator discontinuous multilayers

This work presents the results of the study of structural and electrical transport properties of the iron-insulator discontinuous multilayers (DMIMs). SiO2, HfO2, and MgO were chosen as the materials for the insulating layers. The discontinuous multilayers were prepared by the sequential magnetron sputtering on ceramic substrates. Obtained systems were annealed at different temperatures in an Ar + N2(2 %) environment using an annealing furnace with a continuous gas flow. Crystal structure analysis showed that the effect of annealing on the crystal structure of the samples varies and depends on the annealing temperature and the type of insulator. It has been demonstrated that the formation of iron oxide during annealing can be reduced by using HfO2 as the insulating layer material. The resistivity and temperature coefficient of resistance variation with temperature and the effective thicknesses of the ferromagnetic layers were analyzed. •The dependence of electrical transport properties of the DMIMs [Fe/I]n on the type of insulator has been investigated.•The annealing effect on the sample's crystal structure depends on the annealing temperature and the type of insulator.•For all systems with dFe = 2–3 nm, the insulator regime of conductance was observed regardless of the type of insulator.•In the case of [Fe/HfO2]10/Sub systems, peculiarities in the temperature dependence of resistivity and TCR are observed.