Fabrication and transport studies on PrBa2(Cu1-xMx) O-3(7): M = Ga, Zn, and Co

We have fabricated M-doped PrBa2Cu3O7 (Pr123), i.e. PrBa2(Cu1-xMx)(3)O-7 fo r M = Zn, Ga, and Co, with x = 0.05, 0.10, 0.15, and 0.20. Experimental dat a indicates single phase samples for the Ga and Cc doping up to 20% level. Second phases appear in Zn-doped samples when the doping level reaches 0.15 . At 77 K the electrical resistivity of these compounds is several orders o f magnitude higher than that of undoped Pr123. We also found no orthorhombi c to tetragonal phase transition in the doped samples with all samples rema ining in orthorhombic. Their lattices parameters are very close to those of YBa2Cu3O7-delta (Y123). For this reason these compounds may serve as impro ved buffer-layer materials for Y123 superconducting electronic circuits and devices. (C) 2001 Elsevier Science B.V. All rights reserved.