The system ${\mathrm{Y}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Pr}}_{\mathit{x}}$${\mathrm{Ba}}_2$${\mathrm{Cu}}_{3\mathrm{-}\mathit{y}}$${\mathrm{Fe}}_{\mathit{y}}$${\mathrm{O}}_{\mathit{z}}$, with x=0 to 1, y=0 and 0.3, and z=6 and 7, has been studied by ac and dc magnetometry to determine the superconducting phase transition temperature, $T_c$, by ${}_{}{}^{57}{}_{}{}^{}\mathrm{Fe}$ Mössbauer spectroscopy to determine the antiferromagnetic phase transition temperature of the Cu(2) site, $T_N$, and by specific-heat measurements to determine γ and the antiferromagnetic ordering temperature of the Pr site, $T_n$. $T_c$ (x,z=7), $T_N$ (x,z=6,7), and $T_n$ (x,z=7) were obtained for x values of 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0. For z=6, $T_N$ changes very little with x [$T_N$(0,6)=415 K and $T_N$(1,6)=350 K], but for z=7, $T_N$ changes sharply with x [$T_N$(1,7)=325 K, $T_N$(0.6,7)=230 K, and $T_N$(0.4,7)≤35 K]. There is no conclusive evidence for overlap of superconductivity and antiferromagnetism. $T_n$ also decreases strongly with decreasing x, $T_n$(1,7)=17 K, while $T_n$(0.4,7)≤2.5 K. The specific-heat measurements show large linear temperature terms. The slope γ increases strongly with x and with the introduction of the Fe probe.

• Received 21 April 1989

DOI:https://doi.org/10.1103/PhysRevB.40.6739