Synthesis of Ultrafine High- $T_{C}$ Superconducting $\mbox{GdBa}_2\mbox{Cu}_3\mbox{O}_{7\mbox{-}{x}}$ Powder

GdBa
₂
Cu
₃
O
_7-x
(Gd123) nanowires were synthesized using a modified sol-gel method in the presence of an excellent surfactant benzene tricarboxylic acid. The obtained results revealed that the decomposition of BaCO
₃
and subsequent formation of the pure Gd123 phase complete after recalcination process at 900°C. Structural study using Rietveld refinement of X-ray diffraction and also electron diffraction patterns indicated an orthorhombic structure with Pmmm space group. It can be deduced that the shape and particle size of the products are greatly affected by the concentration of the surfactant. Magnetic susceptibility measurements showed clear diamagnetic behavior below the critical temperature of about 91.78 K in the nanowires, which is comparable with that in the bulk ones. Temperature dependence of the magnetic susceptibility was also found to be approximately insensitive to the strength of the applied magnetic field.