Structural and magnetic properties of the ruthenium double perovskites Ba2-xSrxYRuO6.

The crystal structures of the series of ordered double perovskites Ba(2-x)SrxYRuO(6) (0 ≤x≤ 2) were studied by high resolution synchrotron X-ray diffraction. The materials displayed a sequence of structures associated with increasing tilting of the corner sharing octahedra. The same sequence of structures can be induced by varying the temperature of appropriate members of the series. Magnetic susceptibility measurements demonstrate the oxides to be antiferromagnets with a Neel temperature of ∼30 K. There is a simple correlation between the Weiss constant θ and the Ru-O-Y bond angle. The two Sr rich oxides (x = 1.8 and 2.0) display an, unusual, sharp minimum in susceptibility at low temperatures that is associated with the reorientation of the spins.