Magnetic Ordering and Superconductivity in the REIrGe (RE = Y, La-Tm, Lu) System
arXiv:cond-mat/0311441 · doi:10.1103/PhysRevB.69.174423
Abstract
We find that the compounds for RE = Y, La-Dy, crystallize in the tetragonal Ibam (UCoSi type) structure whereas the compounds for RE = Er-Lu, crystallize in a new orthorhombic structure with a space group Pmmn. Samples of HoIrGe were always found to be multiphase. The compounds for RE = Y to Dy which adopt the Ibam type structure show a metallic resistivity whereas the compounds with RE = Er, Tm and Lu show an anomalous behavior in the resistivity with a semiconducting increase in as we go down in temperature from 300K. Interestingly we had earlier found a positive temperature coefficient of resistivity for the Yb sample in the same temperature range. We will compare this behavior with similar observations in the compounds RERuGe and REBiPt. LaIrGe and YIrGe show bulk superconductivity below 1.8K and 2.5K respectively. Our results confirm that CeIrGe shows a Kondo lattice behavior and undergoes antiferromagnetic ordering below 8.5K. Most of the other compounds containing magnetic rare-earth elements undergo a single antiferromagnetic transition at low temperatures (T12K) while GdIrGe, DyIrGe and NdIrGe show multiple transitions. The T's for most of the compounds roughly scale with the de Gennes factor. which suggests that the chief mechanism of interaction leading to the magnetic ordering of the magnetic moments may be the RKKY interaction.
25 pages, 16 figures