Magnetic doping effects on the superconductivity of Y1-xMxBa2Cu3O7-δ (M = Fe, Co, Ni)

The discovery of superconductivity in copper oxide compounds has attracted considerable attention over the past three decades. The high transition temperature (T-c) in these compounds, exhibiting proximity to an antiferro-magnetic order in their phase diagrams, remains one of the main areas of research. It is believed that magnetic fluctuations provide substance for the exotic superconductivity observed in these compounds. The present study attempts to introduce Fe, Co and Ni magnetic impurities into the superconducting cuprate YBa2Cu3O7-delta with the aim of exploring the T-c behavior. The solid-state synthesis method is exploited to prepare fully oxygenated Y1-xMxBa2Cu3O7-delta (Y1-xMx-123) (M = Co, Fe, Ni) samples with low levels of doping (0.00000 < x < 0.03000). Systematic measurements are then employed to assess the synthesized samples using AC magnetic susceptibility, electrical resistivity and X-ray diffraction (XRD). The measurements revealed an increase in T-c as a result of magnetic substitution for Y. However, the study of non-magnetic dopings on the fully oxygenated Y1-xMx'Ba2Cu3O7-delta (Y1-xMx'-123) (M' = Ca, Sr) samples showed a decrease in T-c. Quantitative XRD analysis further suggested that the internal pressure could have minor effects on the increase in T-c. The normal state resistivity vs temperature showed a linear profile, confirming that the samples are at an optimal doping of the carrier concentration.

Automated summary

The study introduced Fe, Co and Ni magnetic impurities into superconducting cuprate YBa2Cu3O7-delta, resulting in an increase in Tc, while non-magnetic dopings showed a decrease in Tc.