Effect of Ni and Zn substitution on magnetic properties of the high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{GdBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{7\mathrm{-}\mathit{y}}$

Magnetic properties of ${\mathrm{GdBa}}_2$(${\mathrm{Cu}}_{1\mathrm{-}\mathit{x}}$ ${\mathit{M}}_{\mathit{x}}$ ${)}_3$ ${\mathrm{O}}_{7\mathrm{-}\mathit{y}}$ were studied with M=Ni, Zn and x=0, 0.025, 0.050, 0.075, and 0.100. All samples are single phase with orthorhombic oxygen-deficient perovskite structure. Substitution of Cu by Ni or Zn not only depresses superconductivity but also reduces the antiferromagnetic ordering temperature ${\mathit{T}}_{\mathit{N}}$ of Gd ions, suggesting an interaction between Gd ions and the Cu-O plane. The effect of Ni on ${\mathit{T}}_{\mathit{N}}$ is the same as that of Zn. For x=0.10, both Ni- and Zn-substituted compounds are nonsuperconducting. A deviation from Curie-Weiss behavior is observed at about 8 K for these nonsuperconducting compounds. A possible explanation is discussed.