High-resolution neutron diffraction determination of noncollinear antiferromagnetic order in the honeycomb magnetoelectric Fe${}_4$Nb${}_2$O${}_9$

Abstract

Magnetoelectric systems offer potential for device applications exploiting coupled states between electric and magnetic properties. Among magnetoelectric materials, \FNO has attracted special attention because of its pronounced dielectric signal at high magnetic transition temperatures. However, the magnetic ground state, which is essential information for understanding its unusual magnetoelectricity, remains unclarified. Here, we report a noncollinear magnetic ground state of Fe${}_4$Nb${}_2$O${}_9$. To examine the magnetoelectric effect associated with sequential magnetic and structural transitions upon cooling, we conducted combined x-ray diffraction, magnetic susceptibility, magnetization, dielectric constant, and magnetodielectric experiments. Powder neutron diffraction experiments revealed a series of magnetic Bragg peaks and clear splitting of peaks via structural transition. Magnetic Rietveld refinements, combined with group theory analysis, determined a noncollinear antiferromagnetic structure including a significant $c$-axis moment component at 1.5 K. This study provides insights into the understanding of its magnetoelectric properties.

13 pages, 8 figures, 5 tables, 1 appendix

References in corpus (9)

• Spin current and magneto-electric effect in non-collinear magnets
• Ferroelectricity in the Magnetic E-Phase of Orthorhombic Perovskites
• Anisotropy in the magnetization and magnetoelectric response of single crystalline Mn${}_4$Ta${}_2$O${}_9$
• Noncollinear antiferromagnetic order in the buckled honeycomb lattice of magnetoelectric Co4Ta2O9 determined by single-crystal neutron diffraction
• Successive dielectric anomalies and magnetoelectric coupling in honeycomb Fe${}_4$Nb${}_2$O${}_9$
• Crystallographic and magnetic structure of UNi${}_4$${}^{11}$B
• Noncollinear magnetic order, in-plane anisotropy, and magnetoelectric coupling in a pyroelectric honeycomb antiferromagnet Ni${}_2$Mo${}_3$O${}_8$
• Partial molecular orbitals in face-sharing 3$d$ manganese trimer: Comparative studies on Ba${}_4$TaMn${}_3$O${}_{12}$ and Ba${}_4$NbMn${}_3$O${}_{12}$
• Probing magnetic symmetry in antiferromagnetic Fe4Nb2O9 single crystals by linear magnetoelectric tensor