The PrBa2Cu3O7-delta (Pr 123) system is known to exhibit antiferromagnetic ordering of the Cu spins in the Cu-O planes and chains, in addition to the observed antiferromagnetism due to the ordering of the Pr ions. The antiferromagnetism of the Cu-O planes is generally associated with the insulating nature of transport in Pr 123 and electrical conduction is believed to result through ''hopping'' transport between disordered Cu-O chain segments. However, the possible effects of magnetic ordering in the Cu-O chains on transport properties have not been discussed. If the Cu-O chains play a dominant role in the electrical transport (as suggested by many of the popular theories), then the magnetic ordering of the chains should also be seen in the transport properties. We present magnetization and magnetotransport measurements on single crystal Pr 123 samples which suggest that the magnetism associated with the Cu-O chains does indeed mediate transport in this system. These results confirm that the chains play a significant role in the transport properties and underscore the need for further study of the interplay between magnetism and transport in Pr 123.

The ${\mathrm{PrBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ (Pr 123) system is known to exhibit antiferromagnetic ordering of the Cu spins in the Cu-O planes and chains, in addition to the observed antiferromagnetism due to the ordering of the Pr ions. The antiferromagnetism of the Cu-O planes is generally associated with the insulating nature of transport in Pr 123 and electrical conduction is believed to result through ``hopping'' transport between disordered Cu-O chain segments. However, the possible effects of magnetic ordering in the Cu-O chains on transport properties have not been discussed. If the Cu-O chains play a dominant role in the electrical transport (as suggested by many of the popular theories), then the magnetic ordering of the chains should also be seen in the transport properties. We present magnetization and magnetotransport measurements on single crystal Pr 123 samples which suggest that the magnetism associated with the Cu-O chains does indeed mediate transport in this system. These results confirm that the chains play a significant role in the transport properties and underscore the need for further study of the interplay between magnetism and transport in Pr 123.

The results of magnetoresistance and magnetization measurements taken on a single crystal of PrBa2Cu3O7-delta are reported. Among the family of materials known as the 1-2-3 compounds, only Pr 1-2-3 exhibits non-metallic transport and is not superconducting. Our results suggest that hybridization of Pr orbitals with Cu-O valence states may be responsible for the nonmetallic transport properties of Pr 1-2-3.

The results of magnetoresistance and magnetization measurements taken on a single crystal of PrBa2Cu3O7−δ are reported. Among the family of materials known as the 1-2-3 compounds, only Pr 1-2-3 exhibits non-metallic transport and is not superconducting. Our results suggest that hybridization of Pr orbitals with Cu-O valence states may be responsible for the nonmetallic transport properties of Pr 1-2-3.