Magnetic properties of polycrystalline Pr_xY_1-xBa₂Cu₃ O_7-δ

In this work, we report a part of a systematic study of the influence of the synthesis routes on the properties of polycrystalline samples of Pr_xY_1-xBa₂Cu₃ O_7-δ. We have prepared high-quality samples of this material by following a sol-gel method, associated with heat treatment in both an inert argon and an oxygen atmospheres in order to compare their influence on the formation of the superconducting phase. Magnetic measurement (AC susceptibility) show that the superconducting transition temperature (T_C) increases in samples prepared in argon when compared to those prepared in oxygen, for the same composition and Pr fraction less than 0.5. In addition to this, preliminary results of AC and DC magnetic susceptibility show superconductivity for samples with Pr fraction higher than 0.5 (and up to 0.9) prepared under argon flux, which may indicate the existence of stable superconductivity for all compositions, including pure Pr-123.