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Anderson, A.C. Robichaux, Joseph Emile 2011-07-26T19:49:47Z 2011-07-26T19:49:47Z 10000-01-01 1970 The thermal conductivity was measured in Lanthanum Magnesium Nitrate (LMN) and Cerium Magnesium Nitrate (CMN) in zero external magnetic field and was found to be independent of the particular rare-earth ion which occupied the La site, the concentration of that ion, the thickness of the sample and the condition of its surfaces. The thermal conductivity, measured both in the direction perpendicular to that axis, was observed to vary according to a power of the temperature which lay between 2.8 and 3.0'. It is suggested therefore that the thermal conductivity in the double nitrate crystals is determined by an internal scattering mechanism which is approximately independent of frequency. The phonon mean free paths, calculated in the usual way from the thermal conductivities of the individual samples, were appreciably greater than the smallest dimensions of the respective samples. A depression observed in the thermal conductivity of samples doped with the non-Kramers rare-earth ions Pr+3 and Ho+3 was determined to be caused by the resonant scattering of phonons by these ions due to electronic transitions between the magnetic hyperfine levels. The splitting, in zero external magnetic field, between the hyperfine levels in the Pr+3 ion inCMN is 0.048 K. This splitting in the Ho+3 ion inLMN is estimated to be on the order of or less than 0.03 K. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T19:49:47Z No. of bitstreams: 1 1970_robichaux.pdf: 3144482 bytes, checksum: 36420ddabdb07316250b2218c0efb53a (MD5) Made available in DSpace on 2011-07-26T19:49:47Z (GMT). No. of bitstreams: 1 1970_robichaux.pdf: 3144482 bytes, checksum: 36420ddabdb07316250b2218c0efb53a (MD5) Previous issue date: 1970 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-26T19:49:47Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:33:09-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 6044267 http://hdl.handle.net/2142/25846 en Copyright 1970 Joseph Emile Robichaux, Jr. thermal conductivity double nitrate crystals lanthanum magnesium nitrate cerium magnesium nitrate The thermal conductivity of double nitrate crystals below 1 K Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.