Crystal structures and magnetic properties of ordered perovskites Sr₂LnRuO₆ (Ln = Eu-Lu)

The perovskite-type compounds Sr₂LnRuO₆ (Ln = Eu-Lu) have been synthesized, and their crystal structures and magnetic properties have been investigated. Powder x-ray diffraction measurements and the Rietveld analysis show that they are monoclinic with space group P2₁/n and that Ln³⁺ and Ru⁵⁺ ions are structurally ordered.

These compounds show complex magnetic transitions at low temperatures. These transitions are considered to be antiferromagnetic ones from large negative Weiss constants. Below the transition temperatures, there is a large difference in the temperature dependence of the magnetic susceptibility measured under the zero-field cooled condition and under the field cooled condition, which shows the existence of a weak ferromagnetic moment associated with the antiferromagnetism.