Evidence of a “notch effect” in microwave surface resistance versus deposition temperature for Y1Ba2Cu3O7−x thin film on MgO (100) substrate

Abstract The effect of deposition temperature of Y 1 Ba 2 Cu 3 O 7−x thin film on the microwave surface resistance R s has been studied for films deposited in-situ by cathodic sputtering on MgO (100) single crystal substrate and compared to results obtained on LaAlO 3 (100) single crystal substrates. The measurements of R s were performed at 10 GHz and 77 K using the dielectric resonator method. It was found that YBa 2 Cu 3 O 7−8 films where R s values are lower than 0.5 mΩ were obtained on MgO substrate within an extremely narrow temperature range (1–2 °C). The presence of the lowest R s values were found to be correlated with the lowest RBS yield in channelling geometry ( χ min ) and with the lowest quantity of misaligned c -axis grains.