Answers are grounded in this paper and cite their sources.
The heat capacity of erbium has been measured over the range 15 to 320°K and the thermodynamic functions have been calculated. Three maxima have been observed which occur at 19.9°K, 53.5°K, and 84°K. The two at the lower temperatures show a dependence on the thermal history of the sample, and this dependence was investigated. A correlation of the various contributions to the entropy at room temperature has been made and extended to the other rare earth metals.
No takes yet. Share an insight, caveat, or question.
Skochdopole et al. (1955) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: