Evidence for an unconventional magnetic instability in the spin-tetrahedrasystem Cu2Te2O5Br2 - art. no. 227201

Citation
P. Lemmens et al., Evidence for an unconventional magnetic instability in the spin-tetrahedrasystem Cu2Te2O5Br2 - art. no. 227201, PHYS REV L, 8722(22), 2001, pp. 7201
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW LETTERS
ISSN journal
0031-9007 → ACNP
Volume
8722
Issue
22
Year of publication
2001
Database
ISI
SICI code
0031-9007(20011126)8722:22<7201:EFAUMI>2.0.ZU;2-L
Abstract
Thermodynamic experiments as well as Raman scattering have been used to stu dy the magnetic instabilities in the spin-tetrahedra systems Cu2Te2O5X2, X = Cl and Br. While the phase transition observed in the Cl system at T-N = 18.2 K is consistent with 3D antiferromagnetic ordering, the phase transiti on at T-o = 11.4 K in the Br system has several unusual features. We propos e an explanation in terms of weakly coupled tetrahedra with a singlet-tripl et gap and low-lying singlets.