The symmetry of the spin Hamiltonian in herbertsmithite, a spin-1/2 kagom\'{e} lattice

TL;DR

This study investigates the anisotropic magnetic properties of herbertsmithite, revealing Ising-like exchange anisotropy and proposing an exotic ferromagnetic ground state based on magnetization and muon spin rotation data.

Contribution

It provides new insights into the spin Hamiltonian symmetry of herbertsmithite, highlighting anisotropic exchange interactions and their implications for the ground state.

Findings

Significant magnetization difference along different directions at low fields and high temperatures.

High-temperature behavior indicates Ising-like exchange anisotropy.

Muon spin rotation data consistent with an exotic ferromagnetic ground state.

Abstract

We present magnetization measurements on oriented powder of ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$ along and perpendicular to the orienting field. We find a dramatic difference in the magnetization between the two directions. It is biggest at low measurement fields $H$ or high temperatures. We show that the difference at high temperatures must emerge from Ising-like exchange anisotropy. This allows us to explain muon spin rotation data at $T\to 0$ in terms of an exotic ferromagnetic ground state.