Comment on "Frustrating interactions and broadened magnetic interactions in the edge-sharing CuO_2 chains in La_5 Ca_9 Cu_24 O_41"

TL;DR

This paper uses Monte Carlo simulations to evaluate a 2D anisotropic Heisenberg model for La_5 Ca_9 Cu_24 O_41, finding it fits neutron scattering data but not thermodynamic measurements, suggesting model limitations.

Contribution

It highlights the limitations of the current Heisenberg model in describing all experimental data for La_5 Ca_9 Cu_24 O_41 and proposes possible reasons for discrepancies.

Findings

Model reproduces inelastic neutron scattering data

Model fails to accurately predict magnetization and susceptibility

Suggests need for improved theoretical descriptions

Abstract

Using Monte Carlo techniques, we show that the two--dimensional anisotropic Heisenberg model reproducing nicely inelastic neutron scattering measurements on La_5 Ca_9 Cu_24 O_41 (Matsuda et al. [Phys. Rev. B 68, 060406(R) (2003)]) seems to be insufficient to describe correctly measurements on thermodynamic quantities like the magnetization or the susceptibility. Possible reasons for the discrepancy are suggested.