Crystal structure and magnetic properties of Ba2R2/3TeO6 (R = Y, La, Pr, Nd, Sm-Lu) double perovskites

Abstract

A new series of cubic double perovskites BaTeO6 (R = Y, La, Pr, Nd, Sm–Lu) was synthesized via solid state reaction. The and ions are ordered on alternating octahedral sites, with the rare earth sites 2/3 occupied to balance the charge. The lattice parameters decrease monotonically from for Ba2TeO6 to for Ba2TeO6. The lattice parameter for R = Y is close to that of Ho. Analysis of the resulting bond lengths indicates a structural relaxation around the R ion site. Ba2TeO6, Ba2TeO6 and Ba2TeO6 show primarily temperature-independent magnetic susceptibility due to the lack of a local rare earth moment. For Ba2TeO6 and Ba2TeO6, the susceptibilities are influenced by Van Vleck-like contributions from excited state multiplets. For the remaining members, the Curie–Weiss law is followed with low-temperature deviations that can be associated with various degrees of crystalline electric field splitting. No magnetic ordering was observed down to 1.8 K in any of the compounds.