Incommensurate magnetic order arising from frustrated interchain interactions in the spin-1/2 chain compound AgCuVO$_4$

TL;DR

This study reveals that AgCuVO$_4$ exhibits incommensurate magnetic order due to frustrated interchain interactions, with low ordering temperature and reduced magnetic moments, making it a key model for quantum spin chain frustration.

Contribution

The paper demonstrates the emergence of incommensurate magnetic order in AgCuVO$_4$ driven by frustrated interchain couplings, combining muon spin spectroscopy and neutron diffraction insights.

Findings

Long-range magnetic order at 2.0 K

Incommensurate amplitude-modulated magnetic structure

Reduced ordered magnetic moment of 0.13 μ_B

Abstract

Quantum spin chains with competing interactions offer a platform where low dimensionality and frustration--both acting to suppress magnetic order--intersect. We studied magnetic ordering in the spin-1/2 chain compound AgCuVO$_4$ using muon spin spectroscopy and neutron diffraction. Long-range magnetic order emerges at $T_N = 2.0(1)$ K, which is $\sim$1/200 of the dominant intrachain coupling $J$ and $\sim$1/15 of the interchain interactions. The collinear incommensurate amplitude-modulated magnetic structure features a reduced ordered moment of 0.13(3) $\mu_\mathrm{B}$, confined to the $ab$ plane and modulated along the $c$ axis--perpendicular to the spin chains--indicating frustrated interchain couplings. The low $T_N$, small moment, and incommensurate order highlight strong frustration, positioning AgCuVO$_4$ as a model system for exploring frustration in quantum spin chains.