  The coherence length of the medium-range order (MRO) in metallic liquids is
known to display a Curie-Weiss temperature dependence; its inverse is linearly
related to temperature, and when extrapolated from temperatures above the glass
transition, the coherence length diverges at a negative temperature with a
critical exponent of unity. We propose a mean-field pseudospin model that
explains this behavior. Specifically, we model the atoms and their local
environment as Ising spins with antiferromagnetic exchange interactions. We
further superimpose an exchange interaction between dynamical heterogeneities,
or clusters of atoms undergoing cooperative motion. The coherence length in the
metallic liquid is thus the correlation length between dynamical
heterogeneities. Our results reaffirm the idea that the MRO coherence length is
a measure of point-to-set correlations, and that local frustrations in the
interatomic interactions are prominent in metallic liquids.
