High-pressure synthesis, spin-glass behaviour, and magnetocaloric effects in Fe_xTi₂S₄ heideite sulphides

Abstract

Intercalation compounds based on layered TiS2 sulfide are gaining much attention since the incorporation of transition metals often dramatically change the physical properties and unlocks new intriguing phenomena. Here, we...

Elucidating the Magnetoelastic Coupling, Pressure-Dependent Magnetic Behavior, and Anomalous Hall Effect in FexTi2S4 Intercalation Sulfides

“…Later, the materials were quenched and the pressure was released down to ambient conditions. As demonstrated in our previous work, the temperature plays a pivotal role in stabilizing different amounts of Fe into Fe x Ti 2 S 4 , for instance, x = 0.24 (900 °C), 0.32 (850 °C), and 0.42 (800 °C). From a chemical perspective, the sealed capsule avoids the volatilization of sulfur at the same time promoting the oxidation of Fe to Fe 2+ and the reduction of Ti 4+ to Ti 3+ .…”

“…Although the magnetic properties of Fe x Ti 2 S 4 compounds were previously described in detail, we are now interested in the nature and strength of the magnetic exchange interactions between Fe 2+ and Ti 3+ , which could be FM-like (Fe–S–Ti) or AFM (Fe–S–Fe, Ti–S–Ti). We recall that the magnetic properties stemming from Fe 2+ and Ti 3+ spins offer a complex scenario with antiferromagnetic interactions, characterized by a strongly negative Weiss constant (e.g., θ W = −398 K for x = 0.42), predominant for the Fe-rich phase Fe 0.42 Ti 2 S 4 , combined with FM-like interactions as x decreases (e.g., θ W = 204 K for x = 0.24), leading to spin-glass or cluster-glass behaviors . To shed some light on this problem, we performed high-pressure and low-temperature experiments to evaluate the magnetic susceptibility and magnetization in a range of pressures (up to 1.2 GPa) and temperatures (2–150 K).…”

“…This peak is reduced for x = 0.32 and even more significantly for x = 0.24. We therefore propose that these latter two samples exhibit rather a cluster-glass behavior 9 with the coexistence of a metastable phase composed of AFM and FM clusters in the temperature range from 100 to 200 K.…”

“…We recall that the magnetic properties stemming from Fe 2+ and Ti 3+ spins offer a complex scenario with antiferromagnetic interactions, characterized by a strongly negative Weiss constant (e.g., θ W = −398 K for x = 0.42), predominant for the Fe-rich phase Fe 0.42 Ti 2 S 4 , combined with FM-like interactions as x decreases (e.g., θ W = 204 K for x = 0.24), leading to spin-glass or cluster-glass behaviors. 9 To shed some light on this problem, we performed high-pressure and low-temperature experiments to evaluate the magnetic susceptibility and magnetization in a range of pressures (up to 1.2 GPa) and temperatures (2−150 K). The temperaturedependent magnetic susceptibility data for the three samples at three different pressures (0, 0.5, and 1.1 GPa) are presented in Figure 5a−c.…”

“…Transition metal chalcogenides have been the subject of numerous studies due to their unique properties and potential interest in the modern high-tech industry, such as transistors, 1 photodetectors, 2,3 electroluminescent devices, 4 catalysis, 5 energy conversion, 6 thermoeletric materials, 7,8 magnetic refrigeration, 9 and various other electronic devices. 10,11 For instance, the thiospinel compounds (Hg,Cd,Fe)Cr 2 S 4 show coexisting colossal magnetoresistance (MR) and magnetocapacitance effects.…”