Accession Number : AD0436359


Title :   THE SPECIFIC HEATS OF SOME ALKALI HALIDES AT VERY LOW TEMPERATURES


Corporate Author : NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) DIV OF PURE PHYSICS


Personal Author(s) : Martin, Douglas L


Report Date : 11 Mar 1963


Pagination or Media Count : 13


Abstract : The specific heats of KI, NaI and KBr were measured in the temperature range 0.5 to 1.5K and the low temperature limiting Debye temperatures found to be 133.1+1.5K, 164.3+1.5K and 173.8+1.5K, respectively. The results are compared with those of other workers and agree, within the combined experimental error (less than 2%), with Debye temperatures calculated from low temperature elastic constant measurements. Results of previous work on LiF are also discussed and there is shown to be excellent agreement between the calorimetric and elastic Debye temperatures. The present measurements were made by means of a novel type of calorimeter in which spring loaded 'feet' are used to establish thermal contact with the crystals and thus overcome difficulties arising from large differential thermal contractions. A previously unsuspected source of error, which may occur in calorimetry when superconducting heat switches are employed, was revealed and is analysed.


Descriptors :   *HALIDES , *ALKALI METAL COMPOUNDS , CRYSTAL LATTICES , ELASTIC PROPERTIES , SODIUM COMPOUNDS , CRYOGENICS , SPECIFIC HEAT , CRYOSTATS , IODIDES , VIBRATION , THERMAL PROPERTIES , BROMIDES


Subject Categories : Inorganic Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE