Low-Temperature Paramagnetism in Calcium Copper(II) Acetate Hexahydrate

Single‐crystal magnetic‐susceptibility measurements have been made on CaCu(OAc)₄·6H₂O between 1.5 and 20°K. The present data cannot be fitted to Fisher's linear chain model with $\text{J\hspace{0.17em}/\hspace{0.17em}k\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}1.4°}\mathrm{K}$ as had been previously reported for data taken at higher temperatures. However, the Curie–Weiss law with a value of $\text{θ\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.18°}\mathrm{K}$ describes both the present data and the previous results. In addition, the low‐temperature results are equally well fitted by the linear chain model with $\text{J\hspace{0.17em}/\hspace{0.17em}k\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}0.095°}\mathrm{K}$ .