SUPPRESSION OF SUPERCONDUCTIVITY IN Y1-XPRXBA2CU4O8 PREPARED BY NITRITE PYROLYSIS METHOD

X-ray diffraction patterns show that samples contain the nearly single 124 phase for x<0.7. Lattice parameters a and b increase with Pr concentration. Thermal stability is reduced with increasing Pr concentration. Zero resistance temperature T(co) decreases monotonically from 80 K at x=0 to 12 K at x=0.65. Room-temperature resistivity changes linearly to x=0.7 and increases abruptly at x=0.75. Thus the critical concentration x(cr) is estimated to be 0.7. Effective magnetic moments of Y1-xPrxBa2Cu4O8 are 3.63, 3.35 and 3.23mu(B) for x=0.2, 0.4 and 0.6, respectively. In addition, the similarities and differences between Y1-xPrxBa2Cu4O8 and Y1-xPrxBa2Cu3O7-y are discussed.