Nanocomposites and Nanomaterials
Admittance of thin SiOx(Fe) composite film
Antonin S.1, Semenenko M.1, Bratus O.1,.Kizjak A.1, Evtukh A.A.1, Fefotov A.K.2
1 V. Lashkaryov Institute of Semicondactor Physics NAS of Ukraine, 41 Nauki ave., Kyiv, 03028, Ukraine
E-mail: antoninsv@gmail.com
2 Belarusian State University, 4 Nezavisimosti ave, Minsk 220030, Belarussia
SiOx thin film structures with iron inclusions were obtained by ion-plasma sputtering the composite target consisting of iron and silicon (Fe and Si) in an atmosphere of argon and oxygen. 
Figure 1 shows the changes in the frequency dependences of the admittance and the phase shift angle as a result of annealing of SiOx(Fe) samples in air at different temperatures. As can be seen, the annealing significantly affects the shape of the curves (f) and (f). In particular, on the dependences of the admittance (f) after heat treatment there are minima, which shift to the region of high frequencies with increasing annealing temperature. In this case, the low-frequency dependence  (f) passes into the region of positive values, which indicates the predominance of the inductive contribution to the admittance at frequencies to the left of the minimum on the curves (f). This behavior of the dependences (f) and (f) may be due to the fact that the admittance of annealed samples with SiOx(Fe) film can be presented by equivalent circuits with the series connection of active and reactive contributions to the impedance. This is evidenced, in particular, by a decrease in the inductive contribution to the admittance with increasing frequency to the left of the minimum in (f) (since L ~ 1 / f × L), and an increase in the capacitive contribution with frequency at high frequencies to the right of the minimum in (f) (since С ~ f × С) (Fig. 1a).

Fig. 1. Frequency dependences of total admittance (f) (a) and phase shift angle (f) (b) for composite SiOx(Fe) thin films, measured after annealing in air at different temperatures: 1 - before annealing, 2 - Ta = 673 K, 3 - Ta = 773 K.