Quantum magnetism in the paratacamite family: towards an ideal kagomé lattice

• Published in: Physical review letters Vol. 98; no. 7; p. 077204
• Main Authors: Mendels, P, Bert, F, de Vries, M A, Olariu, A, Harrison, A, Duc, F, Trombe, J C, Lord, J S, Amato, A, Baines, C
• Format: Journal Article
• Language: English
• Published: United States American Physical Society 16-02-2007
• Subjects: Condensed Matter; Physics; Superconductivity
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.98.077204

We report muon spin rotation measurements on the S=1/2 (Cu2+) paratacamite ZnxCu4-x(OH)6Cl2 family. Despite a Weiss temperature of approximately -300 K, the x=1 compound is found to have no transition to a magnetic frozen state down to 50 mK as theoretically expected for the kagomé Heisenberg antiferromagnet. We find that the limit between a dynamical and a partly frozen ground state occurs around x=0.5. For x=1, we discuss the relevance to a singlet picture.