d5-off-centering induced ferroelectric and magnetoelectric correlations in trirutile-Fe2TeO6

TL;DR

This study reports the rare coexistence of ferroelectricity and magnetoelectric coupling in Fe2TeO6, driven by d5 off-centering and complex magnetic interactions, revealing potential for multifunctional device applications.

Contribution

It demonstrates the first observation of ferroelectricity and magnetoelectric effects linked to d5 off-centering in Fe2TeO6, highlighting the role of specific exchange pathways.

Findings

Ferroelectricity associated with lattice and electron density asymmetry.

Magnetoelectric coupling observed via polarization, voltage, and strain measurements.

Negative nonlinear ME behavior at room temperature.

Abstract

We present the rare existence of d5 off-centering, weak ferroelectric polarization and demonstrate its correlation with observed magnetoelectric (ME) properties in the G type (TN~210 K) antiferromagnet Fe2TeO6 (FTO) compound. The origin of ferroelectricity (FE) is associated with both lattice and asymmetric electron density distribution around the ion cores. ME coupling is observed in magnetic field-dependent polarization, ME voltage, and magnetostrain measurements. Short-range magnetic ordering due to intrabilayer dimeric exchange coupling via the double oxygen bridged Fe-O1-Fe pathway is proposed to play a dominating role to exhibit the negative nonlinear magnetic field dependent ME behavior at 300 K. Interbilayer exchange via Fe-O2-Fe pathways dominantly determines the hysteretic nonlinear magnetic field dependent ME response below TN. The observed nonlinear ME coupling signifies magnetoelasticity as manifested in the temperature and magnetic field-dependent strain measurement. Hence the rare existence of ferroelectricity and magnetoelectric coupling by d5 ion is presented in FTO.