Structure, and magnetic and transport behavior of twinned Ce2Rh3(Pb,Bi)5

Single crystals of a new compound, Ce2Rh3(Pb,Bi)5, have been grown via a flux-growth technique using molten Pb as a solvent. The compound has been characterized by single crystal X-ray diffraction and found to be of the orthorhombic Y2Rh3Sn5 structure type [Cmc21 (No. 36), Z=4] with lattice parameters a=4.5980(2), b=27.1000(17) and c=7.4310(4) Å, with V=925.95(9) Å3. Ce2Rh3(Pb,Bi)5 has a complex crystal structure containing Ce atoms encased in Rh–X (X=Pb/Bi) pentagonal and octagonal channels in [100], with polyanions similar to those found in Ce2Au3In5 and Yb2Pt3Sn5. Magnetization measurements find that Ce2Rh3(Pb,Bi)5 is a quasi-two-dimensional system, where the Ce moments are spatially well-localized. Heat capacity measurements show a transition at the Néel temperature of 1.5 K. Evidence for Fermi surface nesting is found in electrical resistivity measurements, and we argue that Ce2Rh3(Pb,Bi)5 is very near a metal–insulator transition in zero field.