Kagome quantum spin systems in the atacamite family

TL;DR

This paper reports the synthesis, structural analysis, and magnetic characterization of atacamite family compounds, revealing diverse magnetic ground states including antiferromagnetic and ferromagnetic orderings in kagome lattice systems.

Contribution

It introduces new kagome quantum spin systems within the atacamite family and provides detailed magnetic and structural analysis of these compounds.

Findings

EuCu₃(OH)₆Cl₃ orders antiferromagnetically at 15 K

ZnₓCu₄₋ₓ(OH)₆(NO₃)₂ orders antiferromagnetically at 9 K

Haydeeite exhibits ferromagnetic order at 4.2 K

Abstract

We present the hydrothermal synthesis, as well as structural and chemical analysis of single crystals on the compounds EuCu$_{3}$(OH)$_{6}$Cl$_{3}$, Zn$_{x}$Cu$_{4-x}$(OH)$_{6}$(NO$_{3}$)$_{2}$ and haydeeite, MgCu$_{3}$(OH)$_{6}$Cl$_{2}$ all arising from the atacamite family. Magnetic and specific-heat measurements down to 1.8 K are carried out for these systems. EuCu$_{3}$(OH)$_{6}$Cl$_{3}$ has a frustrated antiferromagnetic Cu$^{2+}$ ground state with order at 15 K, a strong anisotropy and increased magnetization from Van Vleck paramagnetic Eu$^{3+}$ contributions. ZnCu$_{3}$(OH)$_{6}$(NO$_{3}$)$_{2}$ reveals antiferromagnetic order at 9 K and measurements on haydeeite single crystals confirm the ferromagnetic order at 4.2 K with the easy axis within the kagome plane. These results prove that the atacamite family presents a broad class of materials with interesting magnetic ground states.