Magnetoelastic study on the frustrated quasi-one-dimensional spin-1/2 magnet LiCuVO$_4$

TL;DR

This study explores the magnetoelastic properties of LiCuVO$_4$, revealing evidence of a spin-nematic phase near saturation through magnetostriction and magnetization measurements in high magnetic fields.

Contribution

It provides the first experimental evidence of a spin-nematic phase in LiCuVO$_4$ using magnetostriction and magnetization data, supported by numerical modeling.

Findings

Magnetostriction and magnetization saturate near 54 T.

Gradual evolution indicates spin-nematic phase below saturation.

Exchange-striction mechanism explains observed magnetostriction.

Abstract

We investigated the magnetoelastic properties of the quasi-one-dimensional spin-1/2 frustrated magnet LiCuVO$_4$. Longitudinal-magnetostriction experiments were performed at 1.5 K in high magnetic fields of up to 60 T applied along the $b$ axis, i.e., the spin-chain direction. The magnetostriction data qualitatively resemble the magnetization results, and saturate at $H_{\text{sat}} \approx 54$ T, with a relative change in sample length of $\Delta L/L \approx 1.8\times10^{-4}$. Remarkably, both the magnetostriction and the magnetization evolve gradually between $H_{\text{c3}} \approx 48$ T and $H_{\text{sat}}$, indicating that the two quantities consistently detect the spin-nematic phase just below the saturation. Numerical analyses for a weakly coupled spin-chain model reveal that the observed magnetostriction can overall be understood within an exchange-striction mechanism. Small deviations found may indicate nontrivial changes in local correlations associated with the field-induced phase transitions.