The growth of c-axis oriented Bi2Sr2CaCu2O8+δ thick films from melts with yttrium oxide (Y2O3) addition grown by Liquid Phase Epitaxy (LPE)

Abstract

One of the fields of superconductivity research today involves the processing of high-Tc materials into usable forms such as wires, cables and films. In order for physicists and material scientists to understand them well enough for practical production, it essential that these materials be prepared in better forms. The knowledge of the growth behavior in the Bi-Sr-Ca-Cu-O system, besides knowing its phase relationship, is indispensable in the optimization of the growth conditions of the Bi₂Sr₂CaCu₂O_8+δ (Bi-2212) superconductive phase. The Bi-2212 is the most frequently studied among the three phases of the BSCCO system due to the following considerations: (1) structural simplicity, (2) ease in its fabrication, (3) its chemical stability in ambient atmosphere and (4) its relatively high critical transition temperature.
The Liquid Phase Epitaxy (LPE) method was chosen for this particular study due to the following reasons. (1) method is performed under atmospheric pressure, (2) growth of material performed under near equilibrium conditions and (3) growth rate is relatively faster in this technique compared to other growth methods.
Preliminary studies on the growth mechanism of Bi-2212 film on MgO substrate by the LPE method has already been carried out but many aspects of its growth kinetics are still not fully understood. In the present work, attention was paid on the effects of the intentional addition of dopant into the melt in the form of Y₂O₃, the growth temperature, the growth time and the annealing process in the formation of the Bi-2212 phase. Substrate rotation was also employed to facilitate homogenous growth of the material. These growth parameters have been adapted for the study in the hope that better Bi-2212 samples be prepared.