Effect of oxygenation process on flux pinning in pristine and BaHfO3 nanocomposite GdBa2Cu3O7 superconducting thin films

Abstract

Abstract Pristine and BaHfO3 (BHO) nanocomposite GdBa2Cu3O7 (GdBCO) superconducting thin films were deposited at 800 °C, 0.4 mbar O2 partial pressure using a Nd:YAG laser (λ=355 nm) with 10 Hz frequency on MgO substrate. The influence of the oxygenation process on flux pinning and electrical transport properties was investigated by changing the annealing temperature (T ann) between 450 °C and 780 °C and the holding time (t hold) between 10 and 30 min. The irreversibility field shows the largest shift toward higher fields for T ann = 450 °C and thus the largest in-field J c. Angular dependence of J c for most of the pristine GdBCO films exhibits a large peak for B‖c, however the sample with T ann = 550 °C has a large peak in the 90°-120° region, i.e. near B ‖ ab. For BHO nanocomposites, a decrease in T ann increases in-field J c by a factor of 2.