Successive dielectric anomalies and magnetoelectric coupling in honeycomb Fe${}_4$Nb${}_2$O${}_9$

Abstract

By combining single crystal x-ray and neutron diffraction, and the magnetodielectric measurements on single crystal Fe4Nb2O9, we present the magnetic structure and the symmetry-allowed magnetoelectric coupling in Fe4Nb2O9. It undergoes an antiferromagnetic transition at TN=93 K, followed by a displacive transition at TS=70 K. The temperature-dependent dielectric constant of Fe4Nb2O9 is strongly anisotropic with the first anomaly at 93 K due to the exchange striction as a result of the long range spin order, and the second one at 70 K emanating from the structural phase transition primarily driven by the O atomic displacements. Magneticfield induced magnetoelectric coupling was observed in single crystal Fe4Nb2O9 and is compatible with the solved magnetic structure that is characteristic of antiferromagnetically arranged ferromagnetic chains in the honeycomb plane. We propose that such magnetic symmetry should be immune to external magnetic fields to some extent favored by the freedom of rotation of moments in the honeycomb plane, laying out a promising system to control the magnetoelectric properties by magnetic fields.

References in corpus (5)

• Universal Window for Two Dimensional Critical Exponents
• Magneto-electric effect in NdCrTiO5
• Magnetodielectric and magnetoelastic coupling in TbFe3(BO3)4
• Spin Dynamics and Magnetoelectric Coupling Mechanism of Co4Nb2O9
• Universal exchange-driven phonon splitting in antiferromagnets

Cited by in corpus (4)

• Noncollinear antiferromagnetic order in the buckled honeycomb lattice of magnetoelectric Co4Ta2O9 determined by single-crystal neutron diffraction
• Probing magnetic symmetry in antiferromagnetic Fe4Nb2O9 single crystals by linear magnetoelectric tensor
• Pressure driven re-entrant magnetoelectric transition in honeycomb $F{e}_{4}N{b}_2{O}_9$
• High-resolution neutron diffraction determination of noncollinear antiferromagnetic order in the honeycomb magnetoelectric Fe${}_4$Nb${}_2$O${}_9$