Ground-state order and spin-lattice coupling in tetrahedral spin systems Cu2Te2O5X2 (X=Br or Cl)
Abstract
High-resolution ac susceptibility and thermal conductivity measurement on Cu2Te2O5X2 (X=Br,Cl) single crystals are reported. For Br-sample, sample dependence prevents one from distinguishing between possibilities of magnetically ordered and spin-singlet ground states. In Cl-sample a three-dimensional transition at 18.5 K is accompanied by almost isotropic behavior of susceptibility and almost switching behavior of thermal conductivity. Thermal conductivity studies suggest the presence of a tremendous spin-lattice coupling characterizing Cl- but not Br-sample. Below the transition Cl-sample is in a complex magnetic state involving AF order but also the elements consistent with the presence of a gap in the excitation spectrum.
- Publication:
-
Physical Review B
- Pub Date:
- May 2004
- DOI:
- 10.1103/PhysRevB.69.180401
- arXiv:
- arXiv:cond-mat/0307647
- Bibcode:
- 2004PhRvB..69r0401P
- Keywords:
-
- 75.10.Jm;
- 75.40.Cx;
- 75.45.+j;
- Quantized spin models;
- Static properties;
- Macroscopic quantum phenomena in magnetic systems;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- version accepted for publication in Phys.Rev.B-Rapid Communication