Formation and characterization of Y : 247 film through spray pyrolysis technique

The synthesis of high temperature superconducting films of Y : 247 (T _c ～ 73 K) have been successfully achieved. The difficulty in synthesis owing to narrow range of stability of Y : 247 has been taken care of through several quenching modes, e.g. quenching of the films synthesized at ～850°C, in air or in liquid nitrogen. The energy dispersive analysis of X-rays (EDAX) and transmission electron microscopy (TEM) studies of the as processed film, Y₂Ba₄Cu₇O_14+x, exhibit nearly correct cationic stoichiometry of 2 :4 :7; also narrow regions (< 50 Å) of minority Y : 124 phase and stacking faults capable of working as flux pinning sites have been invariably found to be present. In addition to Y : 247, Ag admixed films have also been investigated. TheT _c here is ～ 70–75 K which is similar to that of the film without silver. Representative estimates of transport critical current density (J _c) for Y : 247 films is ～10³ A/cm², and with silver corresponding to Y₂Ba₄Cu₇O_14+x (Ag_0.1) is found to be ～ 10⁴ A/cm².