A new oxytelluride: Perovskite and CsCl intergrowth in Ba3Yb2O5Te

Abstract The new oxytelluride Ba 3 Yb 2 O 5 Te was obtained from an alkaline earth flux. Ba 3 Yb 2 O 5 Te crystallizes in the tetragonal space group P 4/ mmm (#123), with a =4.3615(3) A and c =11.7596(11) A, Z =1. The structure combines two distinct building blocks, a Ba 2 Yb 2 O 5 perovskite-like double layer with square bipyramidal coordination of the ytterbium ions, and a CsCl-type BaTe layer. Short range magnetic order is apparent at below 5 K, with the magnetic behavior above this temperature dominated by crystal field effects. The structure may be considered as an analog to the Ruddlesden–Popper phases, where the NaCl-type layer has been replaced by the CsCl-type layer. The two-dimensional magnetic behavior is expected based on the highly anisotropic nature of the structure.