Clarification of the ordering of intercalated Fe atoms in FexTiS2 and its effect on the magnetic properties

In this study, FexTiS2 structures, synthesized by chemical vapor transport technique at Fe concentrations of 0.05, 0.10, 0.15, 0.20 0.25 and 0.33, were observed three-dimensionally using a transmission electron microscope and their corresponding magnetization values were measured using a superconducting quantum interference device. The results show a switch from local in-plane two-dimensional (2D) ordering of \sqrt 3 a and 2a at concentrations below 0.15 to three-dimensional (3D) ordering of 2a   ×   2a   ×   2c at x = 0.20 and 0.25, as well as \sqrt 3 a   ×   \sqrt 3 a   ×   2c superstructures at x = 0.33, although it should be noted that the x = 0.20 sample only had partial ordering of Fe atoms. The type of Fe ordering present in FexTiS2 could be explained by the balance of cohesive energy of neighboring Fe atoms and local strain energy imposed on the host structure due to the formation of Fe clusters. It is also found that the switch from 2D to 3D Fe order coincides with the magnetic measurements, which reveal spin-glass behavior below x = 0.15 and ferromagnetic behavior above x = 0.20. This suggests that the magnetic properties of the FexTiS2 structure are highly influenced by the ordering of Fe atoms between planes.

Source: Acta Crystallographica Section B - May 22, 2021 Category: Chemistry Authors: Chiew, Y.L. Miyata, M. Koyano, M. Oshima, Y. Tags: intercalation scanning transmission electron microscope transmission electron diffraction magnetism research papers Source Type: research