Controlling frustrated magnetism on the kagome lattice by uniaxial-strain tuning

TL;DR

This study demonstrates that applying uniaxial strain to a kagome-lattice compound can tune magnetic frustration, leading to enhanced magnetic order and revealing the role of frustration in quantum magnetic states.

Contribution

We experimentally show how uniaxial stress can control frustration and magnetic ordering in a kagome lattice, providing a new method to study quantum disordered states.

Findings

Transition temperature increases linearly with strain.

Strain releases frustration, promoting magnetic order.

NMR indicates a specific magnetic ordering pattern.

Abstract

It is predicted that strongly interacting spins on a frustrated lattice may lead to a quantum disordered ground state or even form a quantum spin liquid with exotic low-energy excitations. However, a thorough tuning of the frustration strength, separating its effects from those of disorder and other factors, is pending. Here we break the symmetry of a kagome-lattice compound in a controlled manner by applying $in$ $situ$ uniaxial stress. The transition temperature of $\rm Y_3Cu_9(OH)_{18}OCl_8$ is linearly enhanced with strain, $\Delta T_{\rm N}/T_{\rm N} \approx 10\%$ upon in-plane compression of order $1\%$, providing clear evidence for a release of frustration and its pivotal role for magnetic order. Our comprehensive $^1$H NMR results suggest a $\overrightarrow{Q}=(1/3\times 1/3)$ state under unstrained conditions and further reveal an incomplete antiferromagnetic transition with fluctuating moments in this strongly frustrated system.