Effect of a positive temperature coefficient of resistance in thin films of doped strontium barium titanate

Thin films of doped semiconducting barium–strontium titanate (Ba,Sr)TiO3 are prepared by pulsed laser ablation. It is shown that the crystal structure, morphology, and electrical properties of (Ba,Sr)TiO3 thin films are determined primarily by the actual ablation conditions. The ablation regimes of deposition permitting preparation of uniform polycrystalline thin films with a composition close to that of the target and with grain sizes larger than 0.1 ¼m are established. These samples have a positive temperature coefficient of resistance in the phase transition region. The change in the resistivity can be as much as 100%.