Crystal structures and magnetic properties of ordered perovskites Sr(2)LnRuO(6) (Ln = Eu-Lu)

The perovskite-type compounds Sr(2)LnRuO(6) (Ln = Eu-Lu) have been synthesi zed, and their crystal structures and magnetic properties have been investi gated. Powder x-ray diffraction measurements and the Rietveld analysis show that they are monoclinic with space group P2(1)/n and that Ln(3+) and Ru5 ions are structurally ordered. These compounds show complex magnetic transitions at low temperatures. Thes e transitions are considered to be antiferromagnetic ones from large negati ve Weiss constants. Below the transition temperatures, there is a large dif ference in the temperature dependence of the magnetic susceptibility measur ed under the zero-field cooled condition and under the field cooled conditi on, which shows the existence of a weak ferromagnetic moment associated wit h the antiferromagnetism.