Investigation of spin-phonon coupling and local magnetic properties in magnetoelectric Fe2TeO6

TL;DR

This study investigates the spin-phonon coupling and magnetic properties of Fe2TeO6, revealing complex magnetic transitions, short-range correlations, and the role of spin-lattice interactions in its magnetoelectric behavior.

Contribution

It provides new insights into the spin-phonon coupling mechanisms and magnetic dynamics in Fe2TeO6, highlighting the influence of interbilayer exchange interactions.

Findings

Detection of short-range magnetic correlations at 150 K

Observation of spin-phonon coupling below 210 K

Quantification of coupling strength in the range 0.1-1.2 cm^-1

Abstract

Spin-phonon coupling originated from spin-lattice correlation depends upon different exchange interactions in transition metal oxides containing 3d magnetic ions. Spin-lattice coupling can influence the coupling mechanism in magnetoelectric material. To understand the spin-lattice correlation in inverse trirutile Fe2TeO6 (FTO), magnetic properties and phonon spectra are studied. Signature of short-range magnetic correlation induced by 5/2-5/2 dimeric interaction and magnetic anomaly at 150 K is perceived apart from the familiar sharp transition (TN~210K) corresponding to long-range order by magnetization and heat capacity measurement. The magnetic transitions and the spin dynamics are further locally probed by muon spin resonance ({\mu}SR) measurement in both zero fields (ZF) and longitudinal field (LF) mode. Three dynamically distinct temperature regimes; (i) T >TN, (ii) TN>T>150 K, and (iii) T<150 K, are observed. A swift change in spin dynamics is realized at 150K by {\mu}SR, though previous studies suggest long-range antiferromagnetic order. The observation of renormalization of different Raman modes below 210K suggests the existence of spin-phonon coupling in the material. The coupling strength is quantified as in the range 0.1-1.2 cm-1 following the two-spin cluster approximation. We propose that the spin-phonon coupling is mediated by the Fe-O2-Fe interbilayer exchange play a significant role in ME coupling observed in the material.