Polycrystalline samples of YBa2Cu3O7−δ added with small amounts (x = 0.0 - 1.0 wt%)
of Sm2O3 nanoparticles were synthesized via co-precipitation process. The effects of addition
of Sm2O3 nanoparticles on the superconducting properties and crystal structure of
YBa2Cu3O7−δ were thoroughly elucidated. The superconducting transition temperature
(Tc) of each sample was measured by a standard four point probe method. As the addition
of nano-Sm2O3 increases, the reduction of Tc occur from 92 K for x = 0.0 to 80 K for x =
1.0 wt% attributable to oxygen vacancy disorder. The crystal lattice parameters of all samples
were determined by X-ray diffraction (XRD) with the Rietveld refinement technique. It
was found that the samples are predominantly single phase perovskite structure Y-123 with
orthorhombic, small amount of Y-211 and unreacted Sm2O3 secondary phases for samples
x = 0.2 - 1.0 wt%. Besides, the structure from SEM images showed that the structure becomes
more porous than the pure sample and the grain sizes are getting slightly decrease
as the addition of Sm2O3 nanoparticles increase. The addition of nano-Sm2O3 disrupts the
grain growth of YBCO (123), therefore resulting in the degradation of microstructure and
superconducting properties of the samples.