Performance improvement of iron chalcogenide films grown at high laser repetition rates by pulsed laser deposition

For mass production, a high deposition rate is necessary. A powerful approach is to deposit Fe(Se, Te) (FST) superconducting films at a high laser repetition rate by pulsed laser deposition. Hence, the FST films were grown on flexible metallic tapes using pulsed laser deposition at different laser repetition rates to explore the effect of laser repetition rate on the properties. It was found that as the laser repetition rate increases, the crystallinity and stoichiometry of FST films deteriorate, resulting in a degeneration in superconductivity. The critical temperature Tczero$T_{\mathrm{c}}<^>{{\mathrm{zero}}}$ of the FST film deposited at a high repetition rate of 120 Hz dropped to 12.89 K. Furthermore, high-performance FST film was successfully deposited at 120 Hz by increasing the substrate temperature with Tczero$T_{\mathrm{c}}<^>{{\mathrm{zero}}}\ $= 16.96 K and Tconset$T_{\mathrm{c}}<^>{{\mathrm{onset}}}\ $= 18.32 K. The self-field critical current density can reach 1.3 MA/cm2 at 4.2 K. The analysis of the pinning mechanism reveals that normal surface pinning centers play a dominant part in the FST film and are independent of the temperature. The collective pinning theory states that the FST film exhibits & delta;l pinning. The results may offer valuable information for rapid deposition of FST-coated conductors for industrial production.

Automated summary

In this study, we investigated the effect of laser repetition rate on the properties of FST superconducting films deposited by pulsed laser deposition. We found that as the laser repetition rate increases, the crystallinity and stoichiometry of the films deteriorate, resulting in a degeneration in superconductivity. However, by increasing the substrate temperature, we were able to successfully deposit high-performance FST films at a high repetition rate.