Dynamic and thermodynamic properties of the generalised diamond chain model for azurite

TL;DR

This study investigates the magnetic and thermodynamic properties of azurite using a generalized diamond chain model, confirming experimental spectra and predicting significant cooling effects during magnetic field changes.

Contribution

The paper provides detailed analysis of azurite's properties with a generalized diamond chain model, including neutron scattering spectra and magnetocaloric effect predictions.

Findings

Good agreement with neutron scattering experiments

Prediction of strong cooling during adiabatic demagnetization above 30T

Identification of a dominant dimer interaction in azurite

Abstract

The natural mineral azurite Cu3(CO3)2(OH)2 is an interesting spin-1/2 quantum antiferromagnet. Recently, a generalised diamond chain model has been established as a good description of the magnetic properties of azurite with parameters placing it in a highly frustrated parameter regime. Here we explore further properties of this model for azurite. First, we determine the inelastic neutron scattering spectrum in the absence of a magnetic field and find good agreement with experiments, thus lending further support to the model. Furthermore, we present numerical data for the magnetocaloric effect and predict that strong cooling should be observed during adiabatic (de)magnetisation of azurite in magnetic fields slightly above 30T. Finally, the presence of a dominant dimer interaction in azurite suggests the use of effective Hamiltonians for an effective low-energy description and we propose that such an approach may be useful to fully account for the three-dimensional coupling geometry.