Structural, electrical, magnetic, and flux pinning properties of YBCO/Ni superconducting composites: analyses and possible explanations

Abstract

Samples of superconducting composite (100-x)YBa2Cu3O7-δ + xNi (x = 1, 2.5, 5, 7.5, 10 and 15 wt.%) were synthesized. Scanning electron microscope (SEM) images revealed that the grain size of YBCO reduces gradually as Ni content is increased. At the same time segregation of Ni as NiO in patches forms throughout the composite. At low Ni wt.%, it was found that the superconducting state properties improved and then dropped with higher Ni wt.%. Segregated patches of NiO on different length scales were observed. The change in the structural and superconducting state parameters of YBCO and the variation of the magnetic critical current density with improved flux pinning in some composites with Ni additives were ascribed to the Jahn-Teller (JT) distortions and pinning of vortices due to antiferromagnetic NiO patches within the samples.

References in corpus (13)

• Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+d
• Cu NMR evidence for enhanced antiferromagnetic correlations around Zn impurities in YBa2Cu3O6.7
• Evolution of Magnetic and Superconducting Fluctuations with Doping of High-Tc Superconductors
• Temperature dependence of electrical resistivity of high-Tc cuprates - from pseudogap to overdoped regions
• Superexchange coupling and spin susceptibility spectral weight in undoped monolayer cuprates
• Resonant Two-Magnon Raman Scattering in Cuprate Antiferromagnetic Insulators
• Instantaneous Spin Correlations in La2CuO4
• Local Lattice Instability and Superconductivity in La${}_{1.85}$Sr${}_{0.15}$Cu${}_{1-x}$M${}_x$O${}_4$ (M=Mn, Ni, and Co)
• Ni impurity induced enhancement of the pseudogap in cuprate high T_c superconductors
• Zn and Ni doping effects on the low-energy spin excitations in La${}_{1.85}$Sr${}_{0.15}$CuO${}_4$
• Low-temperature critical current of Y1-xCaxBa2Cu3O7-delta thin films as a function of hole content and oxygen deficiency
• The effect of Zn substitution on the state of oxygen deficiency and hole concentration in Y1-xCaxBa2(Cu1-yZny)3O7-d
• Ni-substituted sites and the effect on Cu electron spin dynamics of YBa2Cu{3-x}NixO{7-δ}