Specific Heat of Copper, Silver, and Gold below 30°K

The specific heats of pure copper, silver, and gold have been measured in an automatic calorimeter in the range 2.5-30^∘{}K. Above 20^∘{}K the results on copper and gold differ by up to 1% from the author's previous results on these metals---most probably owing to an unstable germanium thermometer used in the earlier work. The new results are analyzed together with data in the 0.4-3.0^∘{}K range and give the following values for electronic-specific-heat coefficient (γ), electron effective mass (m*m), and low-temperature limiting Debye temperature (Θ₀ᶜ). The error limits are 95% confidence limits from the statistical analysis and do not include possible systematic errors. Copper: γ=165.0±0.2 {μ}cal/^∘{}K² g atom (0.691 ±{} 0.001 mJ/^∘{}K² g atom); m*m=1.38, Θ₀ᶜ=(344.3±0.2)^∘{}K. Silver: γ=152.8±0.2 {μ}cal/^∘{}K² g atom (0.640 ±{} 0.001 mJ/^∘{}K² g atom); m*m=1.00; Θ₀ᶜ=(226.6±0.2)^∘{}K. Gold: γ=164.7±0.3 {μ}cal/^∘{}K² g atom (0.689 ±{} 0.001 mJ/^∘{}K² g atom); m*m=1.08; Θ₀ᶜ=(161.8±0.2)^∘{}K. The results are briefly compared with other recent work on these metals.