Effect of gas-liquid-crystal transitions in oxygen clusters on electric and magnetic activity of localized states in In$_2$O$_3$-SrO ceramic

It has been shown that the overlap of tails of the density of states of the valence and conduction bands leads to the formation of a “negative” gap in the In$_2$O$_3$-SrO ceramic with disordered structure and oxygen clusters in nanovoids. Two types of magnetism are observed. One of them caused by the formation of (dangling bond $+$O$^-_2$ center) complexes has been found in samples saturated with oxygen. The other is associated with the presence of dangling bonds in oxygen-depleted samples. At $T<90.18$ K, when oxygen molecules fall from the walls of nanovoids, small liquid oxygen droplets are formed with the release of a large number of free dangling bonds resulting in the variation of magnetization and electrical conductivity of samples. The effects caused by magnetic phase transitions in clusters of crystal oxygen are manifested at $T<54.8$ K. The variations of the resistance of samples in the interval $T=5$–$300$ K correspond to Mott's law under the dependence of the local activation energy for electron hopping on the state of oxygen clusters.