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Anderson, A.C. Yang, In-Sang 2011-05-17T18:08:51Z 2011-05-17T18:08:51Z 10000-01-01 1988 A knowledge of dislocations is essential for an understanding of many of the physical and mechanical properties of crystalline solids. The low-temperature thermal conductivity of electrically insulating crystals is strongly influenced by dislocations. Measurement of the lattice thermal conductivity, therefore, provides a useful tool for the study of phonon-dislocation interaction. In this thesis, thermal conductivity measurements on plastically deformed LiF and KCl crystals are discussed. LiF crystals were deformed in such a way that four slip systems were activated, in a hope to better understand the frequencydependence of the phonon-dislocation interaction. The results of measurements on LiF samples support the conclusion that phonons are scattered by dislocations through dynamic processes, in agreement with previous measurements. Yet, some fraction of phonons still have long mean-free-paths. Numerical calculations for the mean-free-paths assuming dynamic scattering processes and including phonon focusing effects are in fair agreement with experiments made at low temperatures. Our thermal conductivity measurements on KCl crystals indicate that , at temperatures below 2.0 K, all phonon modes are strongly scattered by dislocations. Heat-pulse measurements on KCl samples support this interpretation. 1-irradiation restores the thermal conductivity of the deformed KCl samples, suggesting that the phonon-dislocation interaction in KCl also is dynamic in nature. The experimental results are compared with numerical calculations assuming dynamic scattering processes. For small dislocation densities, there is reasonable agreement. However, the agreement is poor for heavily deformed samples. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-17T18:08:51Z No. of bitstreams: 1 1988_yang.pdf: 4893965 bytes, checksum: 8b2d60bdeaaedcc6af1119a05d3752a0 (MD5) Made available in DSpace on 2011-05-17T18:08:51Z (GMT). No. of bitstreams: 1 1988_yang.pdf: 4893965 bytes, checksum: 8b2d60bdeaaedcc6af1119a05d3752a0 (MD5) Previous issue date: 1988 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-17T18:08:51Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:16:10-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 3473897 http://hdl.handle.net/2142/23927 en Copyright 1988 In-Sang Yang phonon-dislocation interaction LiF crystals KCl crystals low-temperature thermal conductivity electrically insulating crystals lattice thermal conductivity Study of phonon-dislocation interaction in LiF and KCl crystals Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.