Paramagnetic resonance of transition group ions in crystals with the fluorite structure

The electronic paramagnetic resonance of Co2+ in cubic sites of CaF2 and in trigonal sites of CdF2 have been observed at a frequency of 9 GHz and at liquid helium temperature. The trigonal spectra have an axial symmetry about a (lll) direction with g11 = 2.25 +/- 0.05 and g1 = 4.45 +/- 0.10. The origin of this trigonal center is unknown. The isotropic spectra can be described by a spin Hamiltonian with g = 2.32 +/- 0.01, u=-0.Oil +/- 0.004, A = 27.5 +/- 1.2 x lO-4 cm-1 and U = 3.5 +/- 3.5 x 10-4cm-1. The superhyperfine splitting parameters are estimated to be Af = 2.85 x 10-4cm-1 and Bf = 5.97 x lO-4cm-1. Heat treatment of the doped Ca?2 sample makes the cubic spectra diminish. This phenomenon is explained by a change in the valence' state of the paramagnetic ion. X-ray irradiation of the CaF2 sample doped with Co by diffusion changes the sample to red, but no Co^ + ions are observed. Attempts to convert the cubic spectra to trigonal ones by oxidation and hydrolysis do not yield any result.

Name thesis:degree_name

Master of Arts

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Natural Sciences

Grantor

Rice University

Year dc:date.issued

1970

Author dc:creator

• Shen, Lewis Nai-Sing

Advisor dc:contributor.advisor

• Estle, Thomas L.

Statement dc:rights

• Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1911/90066

OAI identifier oai:identifier

oai:repository.rice.edu:1911/90066