Correlations between magnetic and superconducting properties of Zn-substituted YBa2Cu3O6+x

Abstract

${\mathit{T}}_{\mathit{c}}$ and ${\mathit{T}}_{\mathit{N}}$ (Néel) have been measured for a series of ${\mathrm{YBa}}_2$(${\mathrm{Cu}}_{0.96}$ ${\mathrm{Zn}}_{0.04}$ ${)}_3$ ${\mathrm{O}}_{6+\mathit{x}}$ samples. The T variations of the homogeneous susceptibility ${\mathrm{\chi }}_{\mathit{s}}$ of the ${\mathrm{CuO}}_2$ planes, given by the shift of the ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ NMR line, are found to be nearly unchanged with respect to pure samples for x>0.5, which implies that the charge transfer is negligibly modified by Zn, and that the magentic pseudo-gap is not associated with superconducting pairing. Detection of an unusual Curie contribution to the ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ NMR width for x≥0.5 provides evidence that Zn induces magnetic moments in the ${\mathrm{CuO}}_2$ planes, which play a role in the depression of ${\mathit{T}}_{\mathit{c}}$.