A Mössbauer study of ferrous silicates
Date
1976
Authors
Routcliffe, Peter
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The Mössbauer spectra of three types of ferrous silicates,
almandine garnet, olivine and hedenbergite, have been recorded over a
wide range of temperatures, and the effects on the spectra of substitution
by magnetic or non-magnetic ions have been investigated. A new assignment has been proposed for the 3d spin-allowed
crystal field levels of the Fe²⁺ ion in the 8-fold coordinated site of
almandine garnet.
Several synthetic Ca, Mg and Mn iron-olivines were prepared
and the site populations determined.
The low temperature spectra of fayalite have been investigated
and the two subspectra corresponding to Fe²⁺ in the M(l) and M(2) sites
have been identified. Single crystal studies at high temperatures have
been employed to determine the EFG principal axes at both sites and the
orientation of the hyperfine field at both sites. An estimate of
exchange interactions in the olivine structure has been made from the
compositional variation of Neel point of the Mn-Fe olivines. Natural samples of hedenbergite have been investigated over
a wide temperature range and the hyperfine parameters have been determined.
The spectra of an oriented single crystal are presented, and the
relative peak intensities indicate that a change of orientation of the
EFG principal axes occurs on substitution of Mn²⁺ for Fe²⁺ ions in the
M(l) sites.
Description
Keywords
Citation
Collections
Source
Type
Thesis (PhD)
Book Title
Entity type
Access Statement
License Rights
Restricted until
Downloads
File
Description