Magnetic Properties of Chain Antiferromagnets RbFeSe2, TlFeSe2, and TlFeS2

Abstract

Single crystals of ternary ion chalcogenides RbFeSe2, TlFeSe2, and TlFeS2 are studied by X-ray diffraction, SQUID magnetometry, and Mossbauer spectroscopy. Common structural units of these chalcogenides are tetrahedra of FeCh4 (chalcogen Ch = Se, S), arranged in chains by sharing an edge. It is found that RbFeSe2, TlFeSe2, and TlFeS2 undergo transition to a collinear antiferromagnetic state below temperatures TN = 248, 290, and 196 K, respectively. Their magnetic moments are oriented perpendicular to the axes of the chains of FeCh4 tetrahedra.