Thermodynamic properties of the coupled dimer system Cu$_2$(C$_5$H$_{12}$N$_2$)$_2$Cl$_4$

TL;DR

This paper re-examines the thermodynamic properties of the coupled dimer system Cu$_2$(C$_5$H$_{12}$N$_2$)$_2$Cl$_4$ under magnetic field, incorporating recent experimental findings and spin anisotropy to better explain magnetization and specific heat behaviors.

Contribution

It introduces the inclusion of Dzyaloshinskii-Moriya interaction in modeling the system, improving agreement with experimental data.

Findings

Enhanced fit of magnetization curve with spin anisotropy

Correct trend of specific heat anomaly at low temperature

Reconciliation of experimental observations with theoretical model

Abstract

We re-examine the thermodynamic properties of the coupled dimer system Cu$_2$(C$_5$H$_{12}$N$_2$)$_2$Cl$_4$ under magnetic field in the light of recent NMR experiments [Cl\'emancey {\it et al.}, Phys. Rev. Lett. {\bf 97}, 167204 (2006)] suggesting the existence of a finite Dzyaloshinskii-Moriya interaction. We show that including such a spin anisotropy greatly improves the fit of the magnetization curve and gives the correct trend of the insofar unexplained anomalous behavior of the specific heat in magnetic field at low temperature.