Structural, and Magnetic properties of flux free large FeTe Single crystal

TL;DR

This study synthesizes and characterizes FeTe single crystals, revealing a coupled structural and magnetic phase transition at 70K with antiferromagnetic order, and explores anisotropic electrical and thermal properties.

Contribution

First detailed synthesis and characterization of flux-free FeTe single crystals, elucidating their structural, magnetic, and thermal phase transition behaviors.

Findings

Structural transition at 70K with hysteresis

Antiferromagnetic magnetic transition confirmed by susceptibility

Heat capacity spike indicating coupled phase transition

Abstract

We report synthesis of non superconducting parent compound of iron chalcogenide, i.e., FeTe single crystal by self flux method. The FeTe single crystal is crystallized in tetragonal structure with the P4/nmm space group. The detailed SEM (scanning electron microscopy) results showed that the crystals are formed in slab like morphology and are near (slight deficiency of Te) stoichiometric with homogenous distribution of Fe and Te. The coupled structural and magnetic phase transition is seen at around 70K in both electrical resistivity and magnetization measurements, which is hysteric (deltaT = 5K) in nature with cooling and warming cycles. Magnetic susceptibility (chi-T) measurements showed the magnetic transition to be of antiferromagnetic nature, which is substantiated by isothermal magnetization (M-H) plots as well. The temperature dependent electrical resistivity measured in 10kOe field in both in plane and out of plane field directions showed that the hysteric width nearly becomes double to deltaT = 10K, and is maximum for the out of plane field direction for the studied FeTe single crystal. We also obtained a sharp spike like peak in heat capacity Cp(T) measurement due to the coupled structural and magnetic order phase transitions.