Nonlinear current-voltage (I-V) characteristics with S-type negative differential resistance, as a characteristic feature of the switching effect, are inherent in a variety of transition metal oxides, niobium oxide included. Although this phenomenon has been known for a long time, recent proposals to use oxide-based switching devices as elements of oscillatory neural networks have resumed the interest in this area. In this work, electrical switching in sandwich structures based on anodic films

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... f niobium oxide is studied. After being electroformed, these structures exhibit S-shaped I-V characteristics. As the temperature increases, the threshold voltage decreases, presumably tending to zero at a critical temperature T0, which correlates with the temperature of metal-insulator phase transition of niobium dioxide. Channels consisting of NbO2 are formed in the initial anodic films during the process of electroforming.