Tuning magnetic, lattice, and transport properties in CoNb3S6 via Fe doping

TL;DR

This study explores how Fe doping alters the lattice vibrations, magnetic order, and transport properties of CoNb3S6, revealing tunable magnetic and topological phenomena in this van der Waals antiferromagnet.

Contribution

It provides a detailed analysis of Fe doping effects on lattice dynamics, magnetic transitions, and magneto-transport, highlighting the magnetic structure reconstruction and topological property tuning.

Findings

Fe doping causes a blue shift in phonon modes indicating structural effects.

Magnetic transition temperatures are affected by Fe concentration.

Magneto-transport features like hysteresis and Hall effects are suppressed with increased Fe doping.

Abstract

We present a comprehensive investigation of the effects of Fe doping on the lattice dynamics, magnetic ordering, and magneto-transport properties of the intercalated van der Waals antiferromagnets Co1-xFexNb3S6 (x = 0.1 and 0.3). Temperature- and polarization-dependent Raman scattering measurements reveal a pronounced blue shift of the 180 cm-1 phonon mode with increasing Fe concentration, indicating enhanced sensitivity of lattice vibrations to Fe-induced structural and mass effects. While the temperature evolution of the phonon modes is dominated by conventional anharmonic phonon softening, subtle anomalies observed near the N\'eel temperature for x = 0.1 point to weak spin-phonon coupling. Electrical transport and magnetic susceptibility data show clear signatures of the antiferromagnetic phase transitions at TN ~ 20.5-23.7 K for x = 0.1 and TN ~ 32.0 K for x = 0.3. Out-of-plane magnetization measurements reveal hysteretic behavior with two field-induced transitions for x =0.1, which evolve into a single hysteresis loop at x =0.3, signaling a subtle reconstruction of the magnetic ground state. Magneto-transport measurements for x = 0.1 further display a butterfly-shaped hysteretic magnetoresistance and a weak topological Hall effect; however, both features are strongly suppressed at x = 0.3. These results illustrate the critical role of Fe-induced magnetic structure reconstruction in fine-tuning topological and magnetic transport phenomena in intercalated van der Waals antiferromagnets.