Paper detail

PrBa_2Cu_3O_{7-y}: Superconducting or Anomalously Magnetic?

In PrBa_2Cu_3O_{7-y} (Pr123) single crystals grown by the flux method the kink in the magnetic susceptibility chi_{ab}(T), connected with AFM ordering of Pr, disappears after field cooling (FC) in a field H||ab-plane whereas the kink in chi_c(T) remains unchanged after FC in H||c-axis. This seems to be connected with the coupling between the Pr and Cu(2) sublattices. The Curie constant C determined from the data reported for superconducting Pr123 crystals grown by traveling-solvent floating zone (TSFZ) method (Zou et al, Phys. Rev. Lett., 80, 1074 (1998)) is about one half of that for our flux crystals. Thus, the concentration of Pr in TSFZ crystal seems to be about one half of the nominal for Pr123. Therefore, superconductivity in TSFZ samples is connected most probably with the partial substitution of Pr by nonmagnetic Ba.