Microwave reflective properties of amorphous nanogranular composites (CoTaNb)x(MgO)1-x

Abstract

The most important task of flexible and stretchable electronics is to modify the structure in nanoheterogeneous metal-dielectric media to control the properties of materials and create new small-sized devices based on them. In this paper, we present the results of experimental studies of the structure and microwave reflective properties in the frequency range of 8–12 GHz of amorphous nanogranulated composites (CoTaNb)x(MgO)1−x, 21.73 ≤ x ≤ 73.27 at.% with a thickness of 311–1040 nm. Niobium and tantalum, which are part of the metal alloy, are the most promising metals used in aircraft and rocket engineering, as well as in radio electronics and microprocessor technology, for example, as capacitors. The AFM method revealed a granular structure with a granule size from 70 to 200 nm at a metal alloy content of up to 51.70 at.%. The spectra of the microwave reflectivity as a function of frequency, the dependence of the reflectivity on the metallic phase content and the effective thickness of the composite layer are obtained. It is shown that a significant increase in the microwave reflectivity and its saturation are determined to a greater extent by the metallic phase content than by the effective layer thickness. The results of the experimental effect of magnetic fields with induction up to 0.3 T on the microwave reflectivity of composite films are presented. It is shown that magnetic fields can most effectively change the reflective properties of composites (from 8 % to 29 %) at the extremes of the microwave reflectivity of films with the lowest metallic phase content of 22.61–21.73 at.%. With an increase in the metallic phase content, the maximum change in the microwave reflectivity decreases exponentially.