| Numéro |
J. Phys. Colloques
Volume 49, Numéro C8, Décembre 1988
Proceedings of the International Conference on Magnetism
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|---|---|---|
| Page(s) | C8-1425 - C8-1429 | |
| DOI | https://doi.org/10.1051/jphyscol:19888655 | |
Proceedings of the International Conference on Magnetism
J. Phys. Colloques 49 (1988) C8-1425-C8-1429
DOI: 10.1051/jphyscol:19888655
1 Institut d'Electronique Fondamentale, CNRS UA 022, Bât. 220 Université Paris Sud, F-91405 Orsay Cedex, France
2 Centre d'Etudes Nucléaires, DRF/SPh-MDN, 85X, 38041 Grenoble Cedex, France
3 Laboratoire de Spectrochimie des Eléments de Transition, CNRS UA420, Université Paris-Sud, 91405, Orsay, France
J. Phys. Colloques 49 (1988) C8-1425-C8-1429
DOI: 10.1051/jphyscol:19888655
EXPERIMENTAL EVIDENCES FOR AN HALDANE GAP IN QUASI ONE-DIMENSIONAL ANTIFERROMAGNETS
J. P. Renard1, L. P. Regnault2 et M. Verdaguer31 Institut d'Electronique Fondamentale, CNRS UA 022, Bât. 220 Université Paris Sud, F-91405 Orsay Cedex, France
2 Centre d'Etudes Nucléaires, DRF/SPh-MDN, 85X, 38041 Grenoble Cedex, France
3 Laboratoire de Spectrochimie des Eléments de Transition, CNRS UA420, Université Paris-Sud, 91405, Orsay, France
Abstract
It has been predicted by Haldane that the one-dimensional (1D) Heisenberg antiferromagnet (AF) with integer spin has a singlet ground state separated from the excited states by an energy gap. The striking susceptibility decrease as T → 0 and the absence of long range order in quasi- 1D-AF compounds with S = 1, Ni (C2H8N2)2NO2ClO4 and two other related Ni chains, and in AgVP2S6 support the existence of Haldane gap. More detailed experiments including inelastic neutron scatering in NENP reveal a splitting of the Haldane gap by planar anisotropy, in agreement with numerical calculations.