Zigzag magnetic order in a novel tellurate compound Na$_{4-\delta}$NiTeO$_{6}$ with $\mathit{S}$ = 1 chains

TL;DR

Na$_{4- ext{delta}}$NiTeO$_{6}$ exhibits a unique zigzag magnetic order with S=1 spin chains, revealed through neutron diffraction and supported by first-principles calculations, highlighting its potential for studying novel spin-chain physics.

Contribution

This work reports the first detailed determination of the magnetic structure of Na$_{4- ext{delta}}$NiTeO$_{6}$, revealing a zigzag order and field-tunable magnetism in a transition-metal tellurate.

Findings

Ni$^{2+}$ moments form screw ferromagnetic chains along the a axis.

Chains are coupled antiferromagnetically along b and c axes.

Metamagnetic transition occurs near 0.1 T, indicating a field-induced spin-flip.

Abstract

Na$_{4-\delta}$NiTeO$_{6}$ is a rare example in the transition-metal tellurate family of realizing an $S$ = 1 spin-chain structure. By performing neutron powder diffraction measurements, the ground-state magnetic structure of Na$_{4-\delta}$NiTeO$_{6}$ is determined. These measurements reveal that below $T\rm_{N}$ ${\sim}$ 6.8(2) K, the Ni$^{2+}$ moments form a screwed ferromagnetic (FM) spin-chain structure running along the crystallographic $a$ axis but these FM spin chains are coupled antiferromagnetically along the $b$ and $c$ directions, giving rise to a magnetic propagation vector of $k$ = (0, 1/2, 1/2). This zigzag magnetic order is well supported by first-principles calculations. The moment size of Ni$^{2+}$ spins is determined to be 2.1(1) $\mu$$\rm_{B}$ at 3 K, suggesting a significant quenching of the orbital moment due to the crystalline electric field (CEF) effect. The previously reported metamagnetic transition near $H\rm_{C}$ ${\sim}$ 0.1 T can be understood as a field-induced spin-flip transition. The relatively easy tunability of the dimensionality of its magnetism by external parameters makes Na$_{4-\delta}$NiTeO$_{6}$ a promising candidate for further exploring various types of novel spin-chain physics.