Heat capacities of three paramagnetic alums at low temperatures

✍ Scribed by D.G. Kapadnis

• Publisher: Elsevier Science
• Year: 1956
• Weight: 670 KB
• Volume: 22
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(56)80021-9

✦ Synopsis

The heat capacities of potassium chromic alum, ferric ammonium alum and chrome methylamine alum have been measured in the liquid helium and hydrogen temperature ranges by the method of low temperature adiabatic calorimetry. The specific heats between 1 and 4.2°K have been represented by the relations and 0.135 c~ = T~ + 4.11 X 10 -s Ta J/mole-deg, 0.112 c~ T---Y-+ 3.52 × 10-" Ta J/mole-deg, O. 162 c~ T~ + 3.91 X 10 -a T a J/mole-deg. for the respective alums. The Debye characteristic temperature and the crystalline splitting parameter have been computed for each alum. The values of the former are 77.9°K, 82.3°K and 79.2°I( and of the latter 0.247°K, O. 192°K and 0.273°K respectively for CrK-, FeNH 4 and CrCHsNH 3 alum. These results have been compared with those of other investigators. Finally the observed deviations in the hydrogen temperature region have been reported.