V₂O₃‐Polymer Composite Thermistors

V₂O₃ was incorporated into polymer matrices to produce composite materials with low room‐temperature resistivities and sizable positive temperature coefficient (PTC) resistance effects. In addition, a negative temperature coefficient effect, associated with the semiconductor‐to‐metal phase transition in V₂O₃, was also observed. The resistivity vs temperature curve for these composites resembles a square well with three temperature regimes in which the composite behaves like a semiconductor, a metal, and an insulator. The intensity of the PTC effect for these composites was found to be as large as 10 orders of magnitude.