Specific Heat of Cu(NH3)4(NO3)2

Abstract

The specific heat of Cu${(\mathrm{N}{\mathrm{H}}_{3})}_{4}$${(\mathrm{N}{\mathrm{O}}_{3})}_{2}$ has been studied over the temperature range 1.2-16\ifmmode^\circ\else\textdegree\fi{}K. The results show a broad maximum similar to that reported in other substances that magnetically order in linear chains. By comparing with the calculations of Bonner and Fisher, it is determined that the substance forms antiferromagnetic linear chains with a nearest-neighbor Heisenberg interaction constant of $\frac{J}{k}=(3.70\ifmmode\pm\else\textpm\fi{}0.04)\ifmmode^\circ\else\textdegree\fi{}$K.