Influence of Morphology of Impregnated Composites on Their Conducting Properties and Positron Annihilation

NiO–In₂O₃ composites were synthesized by the impregnation of indium oxide nanoparticles with nickel nitrate salt. The phase composition and microstructure, as well as the conductivity of composites over a wide temperature range, have been studied. The introduction of nickel oxide into the In₂O₃ leads to an increase in its resistance. The time distributions of the annihilation radiation of positrons have been studied in the obtained composites. The results are consistent with the data of studies of free volume in samples by low-temperature nitrogen sorption. The possibility of observing point-charged defects or their clusters in metal oxide composites by the positron method is demonstrated. A correlation is observed between changes in the resistance of impregnated indium oxide samples and the intensity of the positron component associated with annihilation in point-charged defects.