University of Illinois Urbana-Champaign

The thermal conductivity of double nitrate crystals below 1 K

Robichaux, Joseph Emile

This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.

Permalink

https://hdl.handle.net/2142/25846

Description

Title
The thermal conductivity of double nitrate crystals below 1 K
Author(s)
Robichaux, Joseph Emile
Issue Date
1970
Doctoral Committee Chair(s)
Anderson, A.C.
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
  • thermal conductivity
  • double nitrate crystals
  • lanthanum magnesium nitrate
  • cerium magnesium nitrate
Language
en
Abstract
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.
Type of Resource
text
Permalink
http://hdl.handle.net/2142/25846
Copyright and License Information
Copyright 1970 Joseph Emile Robichaux, Jr.

Owning Collections

Dissertations and Theses - Physics
Dissertations in Physics
Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois