The structure, chemistry and magnetic properties of FePbBiO4

Abstract

The compound FePbBiO₄ has been synthesised and has a tetragonal structure (P4₂/mbc, a = 8.48924(9) Å, c = 6.10597(8) Å) that is closely related to FeSb₂O₄. It provides the first example of a compound with this structure that (a) contains only trivalent ions (here Fe³⁺) within the chains of edge-linked octahedra and (b) accommodates Bi³⁺ in the walls of the channels formed between the chains of octahedra. FePbBiO₄ orders antiferromagnetically with a Néel temperature of 24 K; neutron diffraction reveals A-type magnetic order with moments oriented perpendicular to [001]. The magnetic moment of Fe³⁺ at 4 K is 3.74(6) μ_B, slightly lower than that commonly observed for this cation in well-ordered magnetic oxides.