A possible chiral spin-liquid phase in non-centrosymmetric $R$BaCo$_4$O$_7$

TL;DR

This paper proposes a symmetry-based explanation for weak ferromagnetism in certain non-centrosymmetric compounds, suggesting a chiral spin-liquid phase with a coupling between spin chirality and magnetization, enabling new studies of critical behavior.

Contribution

It introduces a novel symmetry approach linking spin chirality and magnetization in non-centrosymmetric materials, proposing a chiral spin-liquid phase as a possible explanation for observed phenomena.

Findings

Coupling between spin chirality and magnetization is symmetry-allowed.

This coupling enables studying the critical behavior of chiral order.

A potential chiral spin-liquid phase is identified in non-centrosymmetric compounds.

Abstract

Based on a symmetry approach, we propose a possible explanation of the weak ferromagnetic component recently observed in YBaCo$_3$FeO$_7$ (Valldor et al. Phys Rev B, $\bf {84}$ 224426 (2011)) and other isostructural compounds in the high-temperature spin-liquid phase. Due to the polar nature of their crystal structure, a coupling between time-odd scalar spin chirality which we suggest as the primary order parameter and macroscopic magnetization is possible as follows from the general form of the appropriate free-energy invariant. The deduced pseudoproper coupling between both physical quantities provides a unique possibility to study the critical behaviour of the chiral order parameter.