Comparisons between Haydeeite, α-Cu₃Mg(OD)₆Cl₂, and Kapellasite, α-Cu₃Zn(OD)₆Cl₂, Isostructural S = 1/2 Kagome Magnets

Abstract

The search for new S = 1/2 kagome antiferromagnets has been an ongoing challenge for the researchers interested in frustrated magnetism. Intrigue has surrounded these materials since the proposal that the high frustration of the kagome antiferromagnet and quantum fluctuations could prevent the formation of conventional Néel order and allow the formation of the resonating valence bond (RVB) state at low temperatures. There remain relatively few examples of S = 1/2 kagome magnets with crystal structures that have 3-fold symmetry, as many feature distortions that lower the crystal symmetry to monoclinic and reduce the degeneracy of the kagome lattice. In this article, we detail the synthesis and preliminary magnetic investigations of a new quantum kagome magnet, haydeeite, α-Cu3Mg(OH)6Cl2. Comparisons with the isomagnetic and isostructural analogue kapellasite, α-Cu3Zn(OH)6Cl2, are discussed.

Two-Dimensional Quantum Antiferromagnets

“…359,360 In this compound the kagome planes are well separated from each other by non magnetic Zn 2+ and Cl − ions. The absence of freezing down to very low temperature as well as NMR and inelastic neutron scattering spectra lead experimentalists to the conclusion that it is a spin liquid.…”

“…Two other compounds have been synthesized recently: vesignieite 379 and haydeeite. 360 As herbertsmithite -and in spite of its slight distorsion -vesignieite seems a rather good model of the AF Heisenberg model but it is found to partially order at T c ∼ J/6. 377,378 This might be mainly due to the presence of DM interactions relatively larger than in herbersmithite.…”

Colloquium : Herbertsmithite and the search for the quantum spin liquid

“…The net result is that kapellasite has no long range order. A magnesium version (haydeeite) is also known which does order ferromagnetically at 4.2K Colman et al, 2010). A calcium version, centennallite, is also known (Sun et al, 2016).…”

Quantum kagome frustrated antiferromagnets: One route to quantum spin liquids

“…Kapellasite, a polymorph of herbertsmithite, has a very similar kagome plane structure where Cu-OH-Cu bonds and angles vary little with respect to Herbertsmithite [67,68]. Although this has a drastic effect on the first-neighbors interaction that switches from anti-to ferro-magnetic, it is interesting to consider further neighbor interactions that should be very similar in the two compounds.…”