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Anderson, A.C. Walker, Frederick Joseph 2011-06-08T16:37:44Z 2011-06-08T16:37:44Z 10000-01-01 1983 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. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T16:37:44Z No. of bitstreams: 1 1983_walker.pdf: 3683590 bytes, checksum: a154bce41eff57d20dad36302d4c0e18 (MD5) Made available in DSpace on 2011-06-08T16:37:44Z (GMT). No. of bitstreams: 1 1983_walker.pdf: 3683590 bytes, checksum: a154bce41eff57d20dad36302d4c0e18 (MD5) Previous issue date: 1983 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-08T16:37:44Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:12:44-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 799407 http://hdl.handle.net/2142/25360 en Copyright 1983 Frederick Joseph Walker low-energy excitations yttria-stabilized zirconia thermal conductivity specific heat dielectric constant thermal expansion Low-energy excitations in yttria-stabilized zirconia Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.