Specific heat of Ni$_{x}$Co$_1-{x}$Cl$_{2}$ compounds at low temperatures

The specific heat of three compounds Ni$_{x}$Co$_{1-x}$Cl$_{2}$ with x = 0.10, 0.18, and 0.90 in the temperature range 2-27 К is measured. Together with previous measurements on NiCl$_{2}$ and CoCl$_{2}$, the results are compared with the theory of spin waves of laminar antiferromagnets.