Substitution Effects on the Magnetic Properties of Fe-Containing Chalcogenides with NiAs-Type Structures

Abstract

The changes in the magnetization processes caused by Se for S substitutions in the layered chalcogenide compounds FexTiS2¡ySey (x 0.5, 0.66) with antiferromagnetic (AF) and ferrimagnetic (FI) orderings, respectively, have been studied by using the magnetization and magnetoresistance measurements. Unusually high values of the coercive fields (Hc up to 56 kOe) have been observed at low temperatures in Fe0.5TiS2¡ySey with the Se content y 0.5, which is ascribed to the presence of an unquenched orbital moment on Fe ions and to the formation of a magnetically heterogeneous state in the vicinity of Hc. The Se for S substitution in Fe0.66TiS2¡ySey leads to the transition from the FI to AF state and to non-monotonous change of Hc with a maximal value 22 kOe an y 0.5.The changes in the magnetic state of FexTiS2¡ySey are suggested to be strongly affected by the distribution of Fe ions and vacancies in cationic layers.