Volume 63, Number 4, August 2003
|Page(s)||597 - 602|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 November 2003|
Magnetic-field dependence of the magnetic excitations in ordered
Laboratory for Neutron Scattering, ETH Zürich & Paul Scherrer Institut 5232 Villigen PSI, Switzerland
2 Ames Laboratory, Department of Physics and Astronomy, Iowa State University Ames, IA 50011, USA
3 Laboratoire Léon Brillouin, CEA/CNRS-Saclay 91191 Gif-sur-Yvette, France
Accepted: 16 June 2003
The effect of an external magnetic field H on the magnetic excitations in ordered is investigated by inelastic neutron scattering on single crystals for the first time. A Zeeman-like renormalization of the magnetic excitations is observed at fixed and up to . Above the renormalization occurs linearly, following the expectation for the crystal electric-field levels at finite fields. However, in the range clear discontinuities mark the successive metamagnetic transitions reported for the ground state of the title compound. The comparison of the magnetic excitations between the antiferromagnetic (), helicoidal () and ferromagnetic () ground state allows, by first principles, the determination of the leading exchange interactions between the rare-earth ions. The quantitative results are put into the context of recent theoretical models.
PACS: 75.10.Dg – Crystal-field theory and spin Hamiltonians / 75.30.Et – Exchange and superexchange interactions / 78.70.Nx – Neutron inelastic scattering
© EDP Sciences, 2003
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