STRUCTURAL AND MAGNETIC-PROPERTIES OF SR(4-X)M(X)IRO(6) (M=CA, ZN, CD, LI, NA)

The compounds Sr4-xCaxIrO6 (x = 0.5, 1, 2, 3, 4) and Sr(3)MIrO(6) (M = Li, Na, Zn, Cd) have been synthesized and studied by X-ray powder dif fraction and SQUID magnetometry. They all adopt the K4CdCl6 structure, with the cations M and Ca occupying only the trigonal prismatic sites in the [001] chains unless x > 1. These compounds which contain only Ir-IV order antiferromagnetically at temperatures between 14 and 22 K, and those which contain only Ir-V show temperature-independent parama gnetism. The development of a self-consistent interatomic potential fo r the Ir-IV-O interaction is described. The lattice parameters predict ed for the K4CdCl6-like phases using this new potential agree with the experimental values to within ca. 2%.