Magnetic Susceptibilities of Single Crystal NiCl2·6H2O and CoCl2·6H2O at Low Temperatures

Abstract

The magnetic susceptibilities of single crystal ${\mathrm{NiCl}}_2\text{·6}{\mathrm{H}}_2\mathrm{O}$ and ${\mathrm{CoCl}}_2\text{·6}{\mathrm{H}}_2\mathrm{O}$ have been measured down to 1.3°K for various orientations. The occurrence of antiferromagnetism in ${\mathrm{CoCl}}_2\text{·6}{\mathrm{H}}_2\mathrm{O}$ below ∼2.3°K is confirmed as is the anisotropy of the $g$ -factor of the ${\mathrm{Co}}^{\mathrm{++}}$ ion over the whole range. It is concluded that ${\mathrm{NiCl}}_2\text{·6}{\mathrm{H}}_2\mathrm{O}$ is antiferromagnetic in the helium region and that the temperature-independence of the powder susceptibility here is caused by the fact that $\mathrm{\chi \perp }$ rises as $T$ falls below $T_N$ .