Classical spin liquid or extended critical range in h-YMnO$_3$?

TL;DR

This study investigates diffuse magnetic excitations in h-YMnO₃, revealing critical-like behavior across a broad temperature range, and proposes a model linking these features to critical spin correlations in a 2D magnetic ground state.

Contribution

It introduces a framework modeling diffuse excitations as critical spin correlations, offering a new perspective on classical spin liquids in frustrated magnets.

Findings

Diffuse, gapless magnetic excitations persist above T_N

Correlation length increases as temperature approaches zero

Model suggests critical spin correlations explain observed features

Abstract

Inelastic neutron experiments on the classical triangular-lattice geometrically frustrated antiferromagnet h-YMnO$_3$ reveal diffuse, gapless magnetic excitations present both below and far above the ordering temperature, $T_N$. The correlation length of the excitations increases as the temperature approaches zero, bearing strong resemblance to critical scattering. We model the scattering as critical spin-spin correlations in a two-dimensional magnetic ground state, and we speculate that this may provide a general framework to understand features typically attributed to classical spin liquids.