STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF (Y/PR)BA2CU4O8 PREPARED BY USING O-2-HIP TECHNIQUE

Phase stability of the ''124'' structure was investigated in the (Y1-xPrx)Ba2Cu4O8 system. In the sample preparation process, sintered ceramics were finally annealed at 1050-degrees-C for 40 h in an Ar-20% O2 gas mixture of 2000 atm using an O2-HIP technique. Nearly single-phase samples were obtained where x = 0.0-0.6. The ''124'' phase did not form in the sample with x = 1.0. With increasing x, the lattice parameters increased and T(c) decreased. Structural correlations and magnetic susceptibility measurements suggested that doped Pr prefers the +3 valence state to the +4 state.