SDW transition of Fe1 zigzag chains and metamagnetic transition of Fe2 in TaFe$_{1+y}$Te$_3$

TL;DR

This study investigates the magnetic phase transitions in TaFe$_{1+y}$Te$_3$, revealing a SDW-type AFM order in Fe1 zigzag chains and a field-induced spin-flop transition of interstitial Fe2, with implications for understanding Fe-based magnetic materials.

Contribution

It provides a detailed analysis of the AFM order and spin-flop transition in Fe1 and Fe2, highlighting the coupling mechanisms and magnetic structure in TaFe$_{1+y}$Te$_3$, a novel Fe-based compound.

Findings

High-temperature AFM transition is SDW-type.

Fe2 undergoes a spin-flop transition at a coercive field.

Resistivity drops sharply across the spin-flop transition.

Abstract

We systematically study the AFM order of Fe1 zigzag chains and spin-flop of excess Fe2 under high magnetic field H through the susceptibility, magnetoresistance (MR), Hall effect and specific heat measurements in high-quality single crystal TaFe$_{1+y}$Te$_3$. These properties suggest that the high temperature AFM transition of the TaFeTe$_3$ layers should be a SDW-type AFM order. Below T$_N$, Fe1 antiferromangetic zigzag chains will induce a inner magnetic field \textbf{H$_{int}$} to interstitial Fe2 and lead Fe2 also forms an AFM alignment, in which the magnetic coupling strength between Fe1 and Fe2 is enhanced by decreasing temperature. On the other hand, the external magnetic field \textbf{H$_{ext}$} inclines to tune interstitial Fe2 to form FM alignment along \textbf{H$_{ext}$}. When \textbf{H$_{ext}$} arrives at the "coercive" field H$_C$, which is able to break the coupling between Fe1 and Fe2, these interstitial Fe2 atoms take a spin-flop from AFM to FM alignment. The local moment of Fe2 is about 4 $\mu_{\textrm{B}}$/Fe. From low field ($<$H$_C$) AFM to high field ($>$H$_C$) FM for Fe2, it also induces sharp drop on resistivity and an anomalous Hall effect. The possible magnetic structure of TaFe$_{1+y}$Te$_3$ is proposed from the susceptibility and MR. The properties related to the spin-flop of Fe2 supply a good opportunity to study the coupling between Fe1 and Fe2 in these TaFe$_{1+y}$Te$_3$ or Fe$_{1+y}$Te with interstitial Fe2 compounds.