Electron paramagnetic resonance studies of beta-alumina, a prototype glass

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1980

DOI:https://doi.org/10.2172/5259489· OSTI ID:5259489

Kurtz, Steven Ross ^[1]

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1. Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physics

Electron paramagnetic resonance techniques are used to study single crystal Na, K, and Li beta-alumina. Color centers are introduced into this material by irradiating the samples with electrons at liquid nitrogen temperature. Using electron paramagnetic resonance and electron nuclear double resonance, the color centers generated in this manner are identified, and their location within the material is determined. For one of these centers, an F⁺ center, the electron spin relaxation rate is measured over the range 2 -20 K using the pulse saturation and recovery technique. These measurements reveal an exceptionally fast relaxation rate with anomalous temperature and microwave frequency dependence. Beta-alumina is a structurally unique system. It is partially disordered and consists of ordered blocks of aluminum oxide separated by planar disordered regions. Extensive measurements have shown that beta-alumina displays properties identical to those observed for glasses at low temperature as a result of this limited structural disorder. These glass-like properties have been explained by proposing that atomic tunneling occurs in beta-alumina at low temperature producing a system of localized two level states. A model is developed which quantitatively describes the electron spin relaxation data. The proposed relaxation mechanism couples the color center spin to the phonon induced relaxation of a nearby localized two level tunneling state. A detailed comparison shows that this model is in good agreement with earlier heat capacity, thermal conductivity, and dielectric susceptibility measurements in beta-alumina.

• Research Organization: Univ. of Illinois, Urbana-Champaign, IL (United States). Dept. of Physics
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 5259489
• Report Number(s): DOE/ER/01198-134; DOE/ER/01198-1321
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CRYSTAL STRUCTURE
F CENTERS
PHYSICAL PROPERTIES
GLASS
SODIUM
POTASSIUM
LITHIUM
ELECTRON SPIN RESONANCE
ELECTRONS
PHYSICAL RADIATION EFFECTS
ALKALI METALS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
COLOR CENTERS
CRYSTAL DEFECTS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
LEPTONS
MAGNETIC RESONANCE
METALS
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
RADIATION EFFECTS
RESONANCE
VACANCIES
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties