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ABSTRACT: Series of (YBa2Cu3O7−δ
)1−x
(Al2O3)
x
samples have been prepared using solid state reaction method. Various amount of nano-sized Al2O3 particles (∼50nm) were added with (x=0, 0.005, 0.01, 0.02, and 0.05). The microstructure and the morphology of the polycrystalline samples have been characterized
by X-ray diffraction (XRD) and atomic force microscopy (AFM). The magneto-transport properties of these samples were investigated
using resistance–temperature (R–T) and current–voltage (I–V) characteristics. All samples showed an orthorhombic structure with a tendency to transformation to tetragonal phase at higher
levels of nanoparticles addition. The morphology of the surface of pure samples reveals a considerable number of weak-links,
randomly oriented and clean grain boundaries. While in samples with nano inclusions, grain boundaries were filled with nanosized
particle and have less number of weak-links. Significant enhancement of the superconducting critical current density J
c
in applied magnetic field was observed due to nano Al2O3 inclusions. However, further increase in the value of x decreases the transition temperature T
c
and the critical current density J
c
. These results were interpreted in terms of the flux pinning mechanisms in granular superconducting networks which leads
to a better basic understanding of the performance of YBCO system in high applied magnetic fields.
KeywordsYBCO-Al2O3 nanoparticles-Critical current density-X-ray diffraction-Atomic force microscopy
Journal of Superconductivity and Novel Magnetism 04/2012; 23(7):1333-1340. · 0.65 Impact Factor
