Magnetic State Selected by Magnetic Dipole Interaction in Kagome Antiferromagnet NaBa$_{2}$Mn$_{3}$F$_{11}$

TL;DR

This study investigates the magnetic ground state of NaBa₂Mn₃F₁₁, revealing a tail-chase 120° structure modulated by incommensurate vectors, primarily selected by magnetic dipole-dipole interactions.

Contribution

The paper demonstrates that magnetic dipole-dipole interactions select the tail-chase 120° structure in a Kagome antiferromagnet, providing insight into the role of long-range interactions in magnetic ordering.

Findings

Magnetic Bragg peaks indexed by propagation vectors $oldsymbol{k}_0$, $oldsymbol{k}_1$, and $oldsymbol{k}_2$.

The 120° tail-chase structure is modulated by incommensurate vectors.

Magnetic dipole-dipole interactions up to the 4th neighbor select the tail-chase structure.

Abstract

We have studied the ground state of the classical Kagome antiferromagnet NaBa$_{2}$Mn$_{3}$F$_{11}$. Strong magnetic Bragg peaks observed in the $d$-spacing shorter than 6.0 \AA\ were indexed by the propagation vectors of $\boldsymbol{k}_{0} = (0,0,0)$. Additional peaks with weak intensities in the range of the $d$-spacing longer than 8.0 \AA\ were indexed by the incommensurate vectors of $\boldsymbol{k}_{1}=(0.3209(2),0.3209(2),0)$ and $\boldsymbol{k}_{2}=(0.3338(4),0.3338(4),0)$. Magnetic structure analysis exhibits that the 120$^{\circ}$ structure with the {\it tail-chase} geometry having $\boldsymbol{k}_0$ is modulated by the incommensurate vectors. The classical calculation of the Kagome Heisenberg antiferromagnet having the antiferromagnetic 2nd-neighbor interaction, the ground state of which is degenerated 120$^{\circ}$ structures with $\boldsymbol{k}_0$, reveals that the magnetic dipole-dipole (MDD) interaction including up to the 4th neighbor terms selects the tail-chase structure. The observed modulation of the tail-chase structure is indicated to be due to a small perturbation such as the long-range MDD interaction or the interlayer interaction.