Synthesis and Magnetic Properties of Rare Earth Oxychalcogenides

Abstract

Geometric magnetic frustration presents experimental and theoretical challenges for the study of magnetism, and rare earth compounds are rich subjects for such research. I report the synthesis of pure (RE)\(_{2}\)O\(_{2}\)S and nearly pure (RE)\(_{2}\)O\(_{2}\)Se compounds for RE = La, Ho-Yb using standard solid state methods, as well as these compounds’ magnetic properties. All RE = Ho-Yb compounds were found to be antiferromagnetic. Er\(_{2}\)O\(_{2}\)X and Tm\(_{2}\)O\(_{2}\)X exhibit no ordering down to 1.8 K and remain candidates for magnetic frustration. Ho\(_{2}\)O\(_{2}\)S, Ho\(_{2}\)O\(_{2}\)Se, Yb\(_{2}\)O\(_{2}\)S, and Yb\(_{2}\)O\(_{2}\)S order at T\(_{N}\) = 2.4 K, 4.4 K, 2.7 K, and 1.9 K, respectively; none of these systems are frustrated at low temperature. Both series are promising starting points for further magnetic studies, particularly in the search for geometrically frustrated oxychalcogenide pyrochlores.