Skip to Main content Skip to Navigation
Theses

Résonance paramagnétique électronique de BaCu2Ge2O7: matériau modèle pour l'étude des chaînes de spins quantiques avec interaction Dzyaloshinskii-Moriya

Abstract : BaCu2Ge2O7 is the best AFM S=1/2 spin chain compound exhibiting the Dzyaloshinskii-Moriya (DM) interaction with exchange constant J=540K and TN=8.5K. We have performed multifrequency antiferromagnetic resonance measurements (AFMR) which allow us to show two sources of induced staggered field (hST): the DM interaction and the g tensor. We have also directly measured the amplitude of DM interaction. X band EPR measurements have shown a linear T behaviour of ΔH(T), a relative inversion of ΔH(T) of the principal axis at low temperature and the absence of critical phenomena of the EPR line near TN. The observed discrepancy between χEPR and χStatic shows the possible existence of a second EPR mode. High frequency EPR measurements have shown that in absence of hST, ΔH(T) is independent of H but in presence of hST, ΔH(T) diverge like (hST/T)² in agreement with the recent d'Oshikawa-Affleck's theory.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00010915
Contributor : Sylvain Bertaina <>
Submitted on : Tuesday, November 8, 2005 - 4:12:05 PM
Last modification on : Friday, January 25, 2019 - 2:48:10 PM
Long-term archiving on: : Friday, April 2, 2010 - 10:11:28 PM

Identifiers

  • HAL Id : tel-00010915, version 1

Collections

Citation

Sylvain Bertaina. Résonance paramagnétique électronique de BaCu2Ge2O7: matériau modèle pour l'étude des chaînes de spins quantiques avec interaction Dzyaloshinskii-Moriya. Matière Condensée [cond-mat]. Université de droit, d'économie et des sciences - Aix-Marseille III, 2005. Français. ⟨tel-00010915⟩

Share

Metrics

Record views

326

Files downloads

219