It was found that to annealing temperature 523 K in measurement temperatures a less than room temperature a weak dependence of dielectric type of conductivity occurs in materials – the conductivity increases with temperature increase. At temperatures above room temperature a phase transition dielectric-metal is observed and a conductivity decreases with temperature increase. Growth stage of conductivity was observed in the frequency range above 105 Hz. The relaxation time for this stage is of the order 10-6 s. Annealing in the temperature above 523 K led to the appearance of additional low temperature stage of conductivity, for which the relaxation time is of the order of 10-4 s. The appearance of the low-frequency stage of conductivity increase is associated with oxidation of surface of nanoparticles of metallic phase during annealing, the growing barrier of potential and relaxation time. Further increase of annealing temperature above 673 K causes a further increase of the width of the barrier, and activation energy becomes so much that relaxation times for low-frequency stage grown above 10-2 s. Therefore, low-frequency stage is moves further into the area of low frequency and it becomes unnoticeable because it go beyond the lower range (50 Hz) of used meter.
ACCESS THE FULL ARTICLE
Vitalii Bondariev, "AC electric properties of nanocomposite (FeCoZr)0.818(CaF2)0.182 annealed in the tubular furnace," Proc. SPIE 10010, Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies VIII, 100100C (14 December 2016);