Skip to Main content Skip to Navigation
Theses

Ordre magnétique et distribution de charge dans des composés à base de terres rares: ordre multipolaire et "déplacements d'échange"

Abstract : In the present work two formalisms were developed which, in a mean field approach, connect the magnetic structures to the associated charge one. In the ordered phase the new charge periodicities evolve directly from the magnetic periodicities. In the case of 4f distribution modifications, the model permits the identification of the multipolar component in cause. If the charge redistribution occurs by the displacement of the magnetic atoms, the second model surmises the Fourier component of the displacement waves and theirs polarisations. The first phenomena were systematically studied in the NdMg compound, which permitted to validate the proposed model. In the case of TbMg compound the multipolar X ray diffraction may be an alternative for the determination of the magnetic structure, when many models of magnetic structures correspond to the powder neutron diagrams. The existence of atomic displacement waves determined by the exchange couplings were confirmed in GdB6 compound. The magnetic propagation was deduced for the first time in this compound by a powder neutron diffraction study. The different propagations of the displacement structure were found by an X ray diffraction experiment on a single crystal, in agreement to the expected ones.
Document type :
Theses
Complete list of metadatas

Cited literature [14 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00002356
Contributor : Sorana Emilia Luca <>
Submitted on : Tuesday, February 4, 2003 - 3:02:28 PM
Last modification on : Thursday, January 11, 2018 - 6:14:42 AM
Long-term archiving on: : Friday, April 2, 2010 - 6:49:12 PM

Identifiers

  • HAL Id : tel-00002356, version 1

Collections

UJF | CNRS

Citation

Sorana Emilia Luca. Ordre magnétique et distribution de charge dans des composés à base de terres rares: ordre multipolaire et "déplacements d'échange". Matière Condensée [cond-mat]. Université Joseph-Fourier - Grenoble I, 2002. Français. ⟨tel-00002356⟩

Share

Metrics

Record views

310

Files downloads

348