Spin-1/2 kagome compounds: volborthite vs herbertsmithite

TL;DR

This paper compares two spin-1/2 kagome compounds, volborthite and herbertsmithite, to understand their intrinsic magnetic properties, revealing common behaviors and discussing impurity effects influencing their magnetic responses.

Contribution

It provides a comparative analysis of volborthite and herbertsmithite, highlighting intrinsic magnetic behaviors of the kagome antiferromagnet and discussing impurity effects.

Findings

Both compounds show a broad maximum at T ~ J / 4.

Bulk susceptibility approaches a large finite value at T=0.

Similar local susceptibility behavior observed in herbertsmithite.

Abstract

Two kagome compounds, volborthite Cu3V2O7(OH)2-2H2O and herbertsmithite ZnCu3(OH)6Cl2, are compared in order to derive information about the intrinsic properties of the spin-1/2 kagome antiferromagnet. Volborthite shows a broad maximum at T ~ J / 4 and the approach at T = 0 to a large finite value of the bulk magnetic susceptibility chi_bulk as well as the local susceptibility chi_local from NMR measurements. These must be intrinsic properties for the spin-1/2 kagome antiferromagnet, as similar behavior has also been reported in chi_local for herbertsmithite [Olariu A et al. 2008 Phys. Rev. Lett., 100 087202]. Impurity effects that may significantly influence the bulk properties are discussed.