Synthesis, Crystal Structure, and Magnetic Properties of the Linear-Chain Cobalt Oxide Sr5Pb3CoO12

The novel spin-chain cobalt oxide Sr5Pb3CoO12 [P ×2m, a=10.1093(2) ? and c=3.562 51(9) ? at 295 K] is reported. A polycrystalline sample of the compound was studied by neutron diffraction (at 6 and 295 K) and magnetic susceptibility measurements (5 to 390 K). The cobalt oxide was found to be analogous to the copper oxide Sr5Pb3CuO12, which is comprised of magnetic-linear chains at an interchain distance of 10 ?. Although the cobalt oxide chains ((mu)eff of 3.64 (mu)B per Co) are substantially antiferromagnetic (thetaW=-38.8 K), neither low-dimensional magnetism nor long-range ordering has been found; a local-structure disorder in the chains might have an impact on the magnetism. This compound is highly electrically insulating.