Magnetic Susceptibility of the Kagome Antiferromagnet ZnCu3(OH)6Cl2

TL;DR

This paper investigates the magnetic susceptibility of ZnCu3(OH)6Cl2 using theoretical models and experimental data, highlighting the effects of Dzyaloshinsky-Moriya interactions and impurity spins on the Kagome lattice antiferromagnet.

Contribution

It provides a detailed analysis of the susceptibility data with theoretical calculations, emphasizing the role of DM interactions and impurity effects in the Kagome antiferromagnet.

Findings

High-temperature susceptibility matches the pure Heisenberg model with J=170 K.

Susceptibility upturn at 75 K attributed to DM interactions.

Intermediate temperature susceptibility follows a power law T^{-0.25}.

Abstract

We analyze the experimental data for the magnetic susceptibility of the material ZnCu3(OH)6Cl2 in terms of the Kagome Lattice Heisenberg model (KLHM), discussing possible role of impurity spins, dilution, exchange anisotropy, and both out-of-plane and in-plane Dzyaloshinsky-Moriya (DM) anisotropies, with explicit theoretical calculations using the Numerical Linked Cluster (NLC) method and exact diagonalization (ED). The high-temperature experimental data are well described by the pure Heisenberg model with J=170 K. We show that the sudden upturn in the susceptibility around T=75 K is due to DM interactions. We also observe that at intermediate temperatures, below T=J, our calculated susceptibility for KLHM fits well with a power law T^{-0.25}.