Symmetric and antisymmetric exchange anisotropies in quasi-one-dimensional CuSe$_2$O$_5$ as revealed by ESR

TL;DR

This ESR study of CuSe$_2$O$_5$ reveals significant symmetric and antisymmetric exchange anisotropies in a quasi-one-dimensional spin chain, consistent with Oshikawa-Affleck theory, highlighting the comparable magnitudes of these anisotropies.

Contribution

The paper provides the first detailed ESR analysis of exchange anisotropies in CuSe$_2$O$_5$, quantifying symmetric and antisymmetric interactions and confirming theoretical predictions.

Findings

Symmetric anisotropic exchange J_c ≈ 0.04J

Dzyaloshinskii-Moriya interaction D ≈ 0.05J

Agreement with Oshikawa-Affleck theory

Abstract

We present an electron spin resonance (ESR) study of single-crystalline spin chain-system CuSe$_2$O$_5$ in the frequency range between 9 GHz and 450 GHz. In a wide temperature range above the N\'{e}el temperature $T_N=17$ K we observe strong and anisotropic frequency dependence of a resonance linewidth. Although sizeable interchain interaction $J_{IC}\approx 0.1 J$ ($J$ is the intrachain interaction) is present in this system, the ESR results agree well with the Oshikawa-Affleck theory for one-dimensional $S=1/2$ Heisenberg antiferromagnet. This theory is used to extract the anisotropies present in CuSe$_2$O$_5$. We find that the symmetric anisotropic exchange $J_c=(0.04 \pm 0.01) \:J$ and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction $D=(0.05\pm 0.01)\:J$ are very similar in size in this system. Staggered-field susceptibility induced by the presence of the DM interaction is witnessed in the macroscopic susceptibility anisotropy.