| 摘 要： | The effects of Nd_2O_3 nanoparticles addition on microstructure,transport and AC susceptibility properties of YBa_2Cu_3O_(7–δ)(Y123) superconductors were systematically investigated using X-ray diffraction(XRD),scanning electron micrograph(SEM),four point probe measurement and AC spectrometer.It was found that the added samples were predominant by Y-123 phase beside small amount of Y-211 and unreacted Nd_2O_3 secondary phases.All added samples preserved the orthorhombic structure similar to the pure sample and no orthorhombic-to-tetragonal transition occurred.The samples became more porous and their grain size significantly decreased with addition of Nd_2O_3.The addition of nano-Nd_2O_3 disturbed the grain growth of Y123,thus resulting in the degradation of superconducting properties of the samples.The superconducting transition temperature(Tc onset) of samples decreased from 92 K for x=0.0 to 78 K for x=1.0 wt.%,which could be attributable to oxygen vacancy disorder.From AC susceptibility result,the inter-and intra-granular loss peaks became wider and broader with increase of Nd_2O_3 addition due to the weakening of grains coupling.On the other hand,the inter-granular critical current density,Jcm,was found to increase with Nd_2O_3 addition and had the highest value at x=0.6,confirming that Nd_2O_3 nanoparticles acted as pinning centers in Y123 matrix.
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