Coupling between Antiferromagnetic and Spin Glass Orders in the Quasi-One-Dimensional Iron Telluride TaFe$_{1+x}$Te$_3$ ($x$=0.25)

TL;DR

This study reveals the coexistence of antiferromagnetic and spin glass orders in quasi-one-dimensional TaFe$_{1+x}$Te$_3$, demonstrating how their interaction leads to large exchange bias, with implications for tuning magnetic properties in transition metal chalcogenides.

Contribution

It uncovers the coexistence and coupling of antiferromagnetic and spin glass orders in TaFe$_{1+x}$Te$_3$, highlighting the role of disordered interstitials and chain interactions in magnetic behavior.

Findings

Coexistence of antiferromagnetic and spin glass states in TaFe$_{1+x}$Te$_3$.

Large exchange bias observed at low temperatures.

Disordered interstitial Fe drives spin glass behavior.

Abstract

Understanding the interplay among different magnetic exchange interactions and its physical consequences, especially in the presence of itinerant electrons and disorders, remains one of the central themes in condensed matter physics. In this vein, the coupling between antiferromagnetic and spin glass orders may lead to large exchange bias, a property of potential broad technological applications. In this article, we report the coexistence of antiferromagnetic order and spin glass behaviors in a quasi-one-dimensional iron telluride TaFe$_{1+x}$Te$_3$ ($x$=0.25). Its antiferromagnetism is believed to arise from the antiferromagnetic interchain coupling between the ferromagnetically aligned FeTe chains along the $b$-axis, while the spin glassy state stems from the disordered Fe interstitials. This dichotomic role of chain and interstitial sublattices is responsible for the large exchange bias observed at low temperatures, with the interstitial Fe acting as the uncompensated moment and its neighboring Fe chain providing the source for its pinning. This iron-based telluride may thereby represent a new paradigm to study the large family of transition metal chalcogenides whose magnetic order or even the dimensionality can be tuned to a large extent, forming a fertile playground to manipulate or switch the spin degrees of freedom thereof.