Fabrication techniques of superconducting devices based on intrinsic Josephson effect

For this samples we followed the annealing processes performed on the WBPSiL1 sample for electrical measurements, which gave interesting results from the point of view of resistivity behavior as a function of the annealing process.
The as-grown c-axis value of 30,58 is in agreement with previous analysis on similar samples obtain by the Torino group [17] and also reported in other publications [16].
After the first treatment of c-axis T= 250°C for 3 hours at 1bar oxygen pressure we noticed a caxis value increase, going to 30,67. Such trend is usually reported as a oxygen depletion from the material [16].
Going on with the treatments, we observed a c-axis decrease for the subsequent annealing at 450°C in oxygen flux for 4 minutes, with a value of 30,61. Such modification can be addressed to an oxygen content increase, which is an important result for the determination of the temperature needed to obtain such process for these particular samples.
By comparing the electrical characteristic on the WBPSiL1 sample treated in the same way, we can make some more considerations: the first electrical measurement had a strange behavior with an increase in resistance before the transition region. One of the possible explanation of this behavior was a possible increase in the unhomogeneity of the oxygen in the crystal, due to the 250°C treatment. By taking a closer look to the pattern we can notice a modification in the shape of the peaks. The (0 0 10) peak is taken as example in the next figure, and besides a displacement of the peak after the 250°C treatment (pattern number 2 in the fig. 40), we also notice a decrease of the intensity and an enlargement of Kα1 and Kα2 peaks, resulting in unique broadened peak. Such modification could be related to the inhomogeneous distribution of oxygen, which is in agreement with the resistance observations.