Partial switching and negative capacitance phenomena are observed in thin film AlV2O5Al devices. It is found that the partially switched device behaves as though the device thickness is decreased. The negative capacitance observed in unswitched and partially switched devices is explained on the basis of the model for the electrical conduction in vacuum evaporated thin films, presented by the authors in previous publications. Computer simulations of the negative capacitance characteristics are shown to have excellent correlation with the experimental character‐sties. Copyright © 1987 WILEY‐VCH Verlag GmbH & Co. KGaA