The effect of substrate and annealing temperatures on the microstructure of La1.85Sr0.15CuO4 thin film in pulsed electron deposition process

When employ pulsed electron deposition to grow high-quality La1.85Sr0.15CuO4 (LSCO) thin film, the effect of the substrate and annealing temperatures on the microstructure are studied in this work. The results revealed that at low substrate temperature superconducting phase cannot be well formed, whereas too high deposition temperature will enhance the thermal expansion mismatch between the film and the substrate, which is responsible for the appearance of the cracks in the film. For the annealing, the optimal temperature is 450 °C, if it is varied, the lost of oxygen at high temperature or the difficulty for absorbing oxygen at low temperature will introduce foreign phases on the XRD patterns.