High Specific Heat Dielectrics and Kapitza Resistance at Dielectric Boundaries.
Abstract
This program has two efforts: Kapitza and thermal properties studies. Two separate Kapitza conductance test facilities have been designed and fabricated for both solid-solid and for solid-liquid He II measurements. Preliminary data has been obtained for copper to thalium chloride interface conductance and also for potassium bromide and lithium fluoride thermal conductance to Helium II. For the latter two materials, the test dewars were designed to allow cleaving of the samples under liquid helium and subsequent irradiation of the cleaved surface with UV laser light. Preliminary experiments have been carried out on the effect of UV induced surface defect centers on the Kapitza conductance of potassium bromide. Thermal properties work has included the measurement of the specific heat and thermal conductivity of the cadmium chromium oxide and zinc chromium oxide spinels and of several cesium chloride structure heavy metal halides in the temperature range of 1.5 to 35K. The specific heat data for the spinels was analyzed in terms of both lattice phonons and magnetic contributions. The dependence of the spinel's thermal conductivity of magnetic fields up to 15T was studied and magnetocaloric data has been obtained. For both the zinc and cadmium spinels, the latter results showed a paramagnetic behavior with demagnetization cooling and magnetization heating
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 12, 1984
- Accession Number
- ADA148476
Entities
People
- B. R. Patton
- J. H. Parker Jr.
- P. W. Eckels
- W. N. Lawless