Heat Capacity of Beryllium below 30°K

Abstract

The heat capacity of high-purity beryllium ($\frac{R_{300}}{R_{4.2}}=1100\mathrm{}$) was measured from 1.4°K to 30°K. The results can be expressed by the sum of contributions proportional to $T$, $T^3$, and $T^5$ with the coefficients (0.1714±0.0008) mJ/M${\left(\mathrm{°}\mathrm{K}\right)}^2$, (0.598±0.020)×${10}^{-3\mathrm{}}$ mJ/M${\left(\mathrm{°}\mathrm{K}\right)}^4$, and (0.18±0.04)×${10}^{-6\mathrm{}}$ mJ/M${\left(\mathrm{°}\mathrm{K}\right)}^6$, respectively. The Debye theta at 0°K (${\Theta }_0$) is (1481±16)°K. The results are in good agreement with some of the recent lattice-dynamical and band-structure calculations and with ${\Theta }_0$ derived from elastic constants. Phonon enhancement of the density of states does not appear important in beryllium. The heat capacity is smaller than the work of previous investigators indicated.