Tunable Itinerant Ferromagnetism in the Two-Dimensional FePd$_2$Te$_2$ Hosting 1D Spin Chains

TL;DR

This study explores the tunable ferromagnetism in 2D FePd$_2$Te$_2$ with 1D spin chains, demonstrating how substitution and chain length variation influence magnetic properties and magnon propagation.

Contribution

It introduces Co and Ni substitution in FePd$_2$Te$_2$, revealing new ferromagnetic members and elucidating the microscopic mechanisms of 1D ferromagnetism in 2D materials.

Findings

FePd$_2$Te$_2$ hosts 1D ferromagnetic spin chains with high anisotropy.

Substituting Co and Ni modulates the magnetic behavior and creates new ferromagnetic compounds.

Magnon dispersion shows strong anisotropy, enabling unidirectional magnon propagation.

Abstract

One-dimensional (1D) magnetism offers unidirectional spin interactions that allow unique tunable properties and unconventional spin phenomena. However, it often suffers from poor stability, limiting practical applications. In this regard, integrating 1D magnetism into two-dimensional (2D) materials enables a promising route to stabilize these systems while preserving their anisotropic magnetic characteristics. Here, we focus on the 2D ferromagnet FePd$_2$Te$_2$ (T$_C$ = 183K), which hosts 1D spin chains and strong in-plane anisotropy. Our first-principles calculations reveal highly anisotropic magnetic exchange interactions, confirming its 1D ferromagnetic nature. We modulate this behavior by Co and Ni substitution and introduce two new members of this family, CoPd$_2$Te$_2$ -- a ferromagnet -- and NiPd$_2$Te$_2$. Our results unveil the microscopic mechanisms governing the behaviour of FePd$_2$Te$_2$ and CoPd$_2$Te$_2$. Furthermore, we also demonstrate that the variation of the chain length is key to modulate magnetism. Finally, we determine the magnon dispersion, showcasing a pronounced anisotropy that enables unidirectional magnon propagation.