Quasi-one-dimensional behavior of ${\left(\mathrm{C}{\mathrm{H}}_3\right)}_2$N${\mathrm{H}}_2$Mn${\mathrm{Cl}}_3$ (DMMC)

The heat capacity of dimethyl ammonium manganese trichloride has been investigated for $1.6<T<\mathrm{}50\mathrm{}$ K. A transition to a three-dimensional antiferromagnetically ordered state has been observed at 3.60 K, which is supported by nuclear-magnetic-resonance and susceptibility measurements. The critical entropy did amount to 3.4%. The magnetic heat capacity in the paramagnetic region could be described very well by a $S=\frac{5}{2}$ Heisenberg linear chain system with $\frac{J}{k}=-5.8\mathrm{}\pm 0.7$ K. The data for $\frac{\mathrm{kT}}{\mathrm{}\left|J\right|\mathrm{}}<1.5\mathrm{}$, together with the earlier data on ${\left(\mathrm{C}{\mathrm{H}}_3\right)}_4$NMn${\mathrm{Cl}}_3$, corroborate the suggested low-temperature behavior of such a system.