Low-energy excitations in yttria-stabilized zirconia

Thermal conductivity, specific heat, dielectric constant and thermal expansion measurements below 2 K on single crystal samples of Zr02 :Y203 with 10.5, 16 and 18 mole % Y2O3 contents exhibit properties typical of glasses. The presence of glass-like excitations having a broad spectrum of energies is indicated by the quadratic temperature dependence of the thermal conductivity and the linear temperature dependence of the specific heat. Excitations with relaxation times on the order of 0.5 sec were observed through the specific heat experiments, which implies the existence of a broad range of relaxation times, as predicted by the tunneling model developed for glasses. This material also possesses a Gruneisen parameter larger than expected for a pure crystalline material with a magnitude similar to that observed in other crystals displaying glass-like low-temperature properties. Changing the Y203 content from 10.5 to 16 mole , increases the number of excitations contributing to the specific heat while the phonon scattering does not change appreciably. Although Zr02:Y203 has a crystal structure, there is disorder arising from defects introduced by the Y203. Two models of these defects in a disordered environment were examined as possible tunneling states. The predictions of these models have been compared with tunneling model parameters derived from the data. Neither model compared favorably with the experimental data.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Walker, Frederick Joseph

Contributors dc:contributor

• Anderson, A.C.

• low-energy excitations
• yttria-stabilized zirconia
• thermal conductivity
• specific heat
• dielectric constant
• thermal expansion

Statement dc:rights

• Copyright 1983 Frederick Joseph Walker

Language dc:language

en

Identifier

799407

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25360