Low-Temperature Heat Capacity of Azurite

Publisher Website
Google Scholar
Abstract
The heat capacity of azurite, Cu3(CO3)2(OH)2, has been measured in the temperature range of 1.7–3.6°K. The characteristic λ‐type heat capacity anomaly associated with the antiferromagnetic‐paramagnetic transition in the crystal has been observed, the Néel point being 1.84°K. The entropy change associated with this transition has been found to be 1.17 cal/deg mole and agrees fairly well with the theoretical value of 1.38 cal/deg mole calculated from R ln (2S+1). The contribution to this entropy change above the Néel temperature was approximately 35%, which indicates a comparatively slow diminution of the short‐range ordering of the Cu++ spins.