Specific heat of InBi below 30 K

Abstract

There was difficulty in establishing good thermal contact with InBi, a very anisotropic material. This is not believed to have affected results from the 2.5–30 K adiabatic calorimeter. However, results from the 0.35–3 K isoperibol calorimeter are a few percent high in the overlap range owing to uncompensated heat loss during heating periods. Consequently there is some uncertainty in the determination of the electronic specific heat but little uncertainty in Debye temperatures above 1 K (because the lattice specific heat is so large). Despite the great anisotropy, mass-layering, and easy cleaving in one direction, the variation of Debye temperature with temperature is quite normal, there being no evidence of two-dimensional behavior (cf. graphite). The preferred analysis gives the electronic specific heat coefficient as 97.1 ± 0.8 μcal K−2 g-at.−1 (406 ± 3 μJ K−2 g-at.−1) and the low temperature limiting value of Debye temperature as 139.8 ± 0.4 K.