Growth mechanism, microstructure, EPMA and Raman studies of pulsed laser deposited Nd1−xBa2+xCu3O7−δ thin films

Studies of growth, microstructure, Raman spectroscopy and annealing effect of pulsed laser deposited Ca-doped NBCO thin films

“…We found a strong dependence of the T c of Nd 0.92 Ca 0.08 Ba 2 Cu 3 O 7−δ films on temperature, like the films grown from a Ba-rich target [23]. The presence of quadratic effects (T 2 ) shows that the factor is set close to its optimum value.…”

“…They were also statistically significant when all effects were considered. The experimental values versus The above models do not have good R 2 values compared with the work on films grown from stoichiometric NBCO targets [21] and Ba-rich NBCO targets [22,23]. The possible explanation is that all the growth parameters have some contribution to the film properties or the chosen parameter ranges are not sufficient to make any significant changes in the growth process.…”

“…The experimental values of T c versus the predicted values of T c from the above statistical model are shown in figure 3(c). The best transition widths are sharper than for stoichiometric [21] and Ba-rich NBCO films [22,23].…”

“…From the R-T curve the superconducting transition temperature, T c (0 ) was determined together with the width of the transition, T c = T (R 90% ) − T (R 10% ) and the ratio of the resistances at 300 and 100 K, r R . Characterization of both the targets and thin films was carried out using EPMA, EDX, WDX and Raman spectroscopy (RS) as described in [23].…”

“…In order to compare the results of the Ca-doped NBCO films with those of the films grown from stoichiometric [21] and Ba-rich NBCO films [22,23], we chose the same experimental plan and procedure for analysis used for the growth of the stoichiometric and Ba-rich NBCO films, which involves just three growth parameters: substrate temperature (T ), oxygen pressure (p) and laser energy density (E). All three were set to three different levels to permit detection of quadratic effects, and the experimental plan chosen was again a Box-Behnken design [17,18].…”