Impedance characteristics and phase-dependent conductivity of ZrO$_{2-x}$ nanopowders produced by vacuum-arc synthesis

The paper presents the results of studying the dielectric characteristics of unstabilized zirconium dioxide nanopowder (ZrO$_{2-x}$) obtained by vacuum-arc deposition at different pressures of argon-oxygen plasma. A comprehensive analysis of the phase composition, morphology, photoluminescent properties and impedance characteristics of three samples differing in the content of tetragonal, monoclinic and suboxide phases is carried out. It is found that the electrical response of the materials is determined by the interaction of the bulk conductivity of the tetragonal matrix, the barrier effects of grain boundaries (especially in the presence of m-ZrO$_2$) and the shunting effect of the conducting phase Zr$_3$O. The sample with the lowest content of the tetragonal phase exhibits minimal impedance, while the most heterophase composition is characterized by pronounced interphase polarization and high dielectric losses.