Superconducting thin films based on La2−xSrxCuO4

Abstract
Superconducting films (300–400 nm thick) of La2−xSrxCuO4 have been prepared by a combined evaporation‐reaction method. Amorphous films of the oxide are formed initially on sapphire substrates at deposition temperatures of 25–400 °C. Crystallized films can then be obtained with the desired tetragonal structure and show superconducting resistive transitions, with onsets between 23–28 K and zero resistivities near 4.2 K. A diamagnetic transition consistent with the onset‐resistive transition is seen for different samples and a critical current density of 0.4 A/cm2 is obtained.