Investigation of Thermodynamic Properties of Cu(NH3)4SO4.H2O, a Heisenberg Spin Chain Compound

TL;DR

This study provides comprehensive experimental and theoretical analysis of the thermodynamic and magnetic properties of Cu(NH3)4SO4.H2O, a Heisenberg spin chain compound, validating models with precise measurements and simulations.

Contribution

It offers detailed experimental data and compares them with exact and numerical models, enhancing understanding of quantum spin chain behavior.

Findings

Magnetic susceptibility and specific heat match Bethe ansatz solutions.

Field-dependent specific heat aligns with theoretical predictions.

Entropy and internal energy behaviors agree with models.

Abstract

Detailed experimental investigations of thermal and magnetic properties are presented for Cu(NH3)4SO4.H2O, an ideal uniform Heisenberg spin half chain compound. A comparison of these properties with relevant spin models is also presented. The temperature dependent magnetic susceptibility and specific heat data has been compared with the exact solution for uniform Heisenberg chain model derived by means of Bethe ansatz technique. Field dependent isothermal magnetization curves are simulated by Quantum Monte Carlo technique and compared with the corresponding experimental ones. Specific heat as a function of magnetic field (up to 7T) and temperature (down to 2K) is reported. Subsequently, the data are compared with the corresponding theoretical curves for the infinite Heisenberg spin half chain model with J=6K. Moreover, internal energy and entropy are calculated by analyzing the experimental specific heat data. Magnetic field and temperature dependent behavior of entropy and internal energy are in good agreement with the theoretical predictions.