Neutron spectroscopy of anomalous rare earth intermetallics and high temperature superconductors
Neutron spectroscopy of anomalous rare earth intermetallics and high temperature superconductors
Crystal field excitations have been observed in the high temperature superconductors REBa2Cu3O7(RE= Dy, Ho, Er, Tm) by inelastic thermal neutron scattering. For the Dy, Ho and Er compounds the crystal field parameters have been refined from initial estimates calculated with Newman's superposition model. These parameters have then been successfully used to calculate the specific heat capacity and polycrystalline susceptibility of the compounds. A series of neutron spectroscopy measurements have been carried out on the heavy fermion compounds CeX2Si2 and (CeLa)Ru2Si2 where X is a transition metal element. These experiments show systematic changes in conduction electron f electron interactions with both conduction electron number and lattice parameter. For the La substituted compounds the linewidth of the scattering shows a temperature dependence characteristic of the Kondo effect. Neutron spectroscopy of CePd3 and four compounds CePd3Bx(x< 0.32) shows scattering on two energy scales. For x< 0.25 the scattering consists of pair of quasielastic peaks with widths of order 10meV and im1meV. The broader linewidth decreases with boron content and is nearly temperature independent. For x= O the narrower line became inelastic at low temperatures in one sample. For x> 0,25 the scattering consists of a narrow quasielastic peak and a broad crystal field excitation from a Γ7 excited state with energy im3meV. The lowest spin-orbit transition in Sm3+ was measured in the metallic compound SmPd3, the first observation of this excitation by inelastic neutron scattering. Spectra were also taken for the intermediate valence compound SmB6 which shows no intermultiplet excitations. We conclude that these are obscured by fast valence fluctuations.
University of Southampton
Culverhouse, Stephen Richard
1989
Culverhouse, Stephen Richard
Culverhouse, Stephen Richard
(1989)
Neutron spectroscopy of anomalous rare earth intermetallics and high temperature superconductors.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Crystal field excitations have been observed in the high temperature superconductors REBa2Cu3O7(RE= Dy, Ho, Er, Tm) by inelastic thermal neutron scattering. For the Dy, Ho and Er compounds the crystal field parameters have been refined from initial estimates calculated with Newman's superposition model. These parameters have then been successfully used to calculate the specific heat capacity and polycrystalline susceptibility of the compounds. A series of neutron spectroscopy measurements have been carried out on the heavy fermion compounds CeX2Si2 and (CeLa)Ru2Si2 where X is a transition metal element. These experiments show systematic changes in conduction electron f electron interactions with both conduction electron number and lattice parameter. For the La substituted compounds the linewidth of the scattering shows a temperature dependence characteristic of the Kondo effect. Neutron spectroscopy of CePd3 and four compounds CePd3Bx(x< 0.32) shows scattering on two energy scales. For x< 0.25 the scattering consists of pair of quasielastic peaks with widths of order 10meV and im1meV. The broader linewidth decreases with boron content and is nearly temperature independent. For x= O the narrower line became inelastic at low temperatures in one sample. For x> 0,25 the scattering consists of a narrow quasielastic peak and a broad crystal field excitation from a Γ7 excited state with energy im3meV. The lowest spin-orbit transition in Sm3+ was measured in the metallic compound SmPd3, the first observation of this excitation by inelastic neutron scattering. Spectra were also taken for the intermediate valence compound SmB6 which shows no intermultiplet excitations. We conclude that these are obscured by fast valence fluctuations.
This record has no associated files available for download.
More information
Published date: 1989
Identifiers
Local EPrints ID: 461949
URI: http://eprints.soton.ac.uk/id/eprint/461949
PURE UUID: 0ed10d8e-aec6-42ae-a323-cc40720be122
Catalogue record
Date deposited: 04 Jul 2022 18:59
Last modified: 04 Jul 2022 18:59
Export record
Contributors
Author:
Stephen Richard Culverhouse
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics