Calorimetric Evidence for a Singlet Ground State inCuCrandCuFe

Abstract

Heat-capacity measurements show that the entropy reduction associated with the formation of the spin-compensated state in $\mathrm{Cu}\mathrm{Cr}$ is $R\ln \mathrm{}(2S+1)\mathrm{}$. The magnetic field dependence of the heat capacity of $\mathrm{Cu}\mathrm{Fe}$ suggests that at $T\ll T_K$ the susceptibility has the form $\chi ={\chi }_0\times [1-15\mathrm{}{\left(\frac{T}{T_K}\right)}^2]$, which is consistent with the third law of thermodynamics.