Suppression of the superconducting gap and the spin-fluctuation gap of ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{\mathit{y}}$ (y=7.0 and 6.76) by Zn substitution as measured by ${\mathrm{Gd}}^{3+}$ electron-spin resonance

The local susceptibility around Zn atoms in Gd-doped ${\mathrm{YBa}}_2$(${\mathrm{Cu}}_{0.97}$ ${\mathrm{Zn}}_{0.03}$ ${)}_3$ ${\mathrm{O}}_{\mathit{y}}$ has been measured by the electron-spin-resonance Knight shift of ${\mathrm{Gd}}^{3+}$ at 245 GHz. The magnitude and distribution of the shifts are compared with the corresponding data for compounds with no Zn. For both y=7.0 and 6.76 the full density of states (corresponding to the high-temperature normal state of the pure y=7.0 compound) is restored at the first-neighbor sites of Zn atoms irrespective of whether the material is superconducting or not. This shows that both the superconducting gap and the spin-fluctuation gap are locally suppressed by Zn substitution.