A single crystal of ${\mathrm{CrSi}}_2$ was grown by a modified floating-zone refining technique, and its magnetic susceptibilities and Hall coefficients in the directions of both the a and c axes were measured over a temperature range from room temperature to 1000 K. The susceptibilities were constantly negative over the temperature range and possessed a minimum value at 770 K. The temperature dependence of the hole concentration estimated from observed data of the Hall measurement suggested that above 770 K the susceptibility is primarily dominated by the contribution from charge carriers. The chemical composition of the crystal was estimated at ${\mathrm{CrSi}}_{1.985}$ by quantitative chemical analysis. A theoretical curve of susceptibility was calculated by assuming that the excess Cr atoms act as ${\mathrm{Cr}}^{3+}$ ions in the crystal. The observed susceptibilities were in good agreement with the theoretical curve. It was concluded that the Cr atoms constituting a stoichiometric ${\mathrm{CrSi}}_2$ lattice are quadrivalent by reason of their negligibly small contribution to the susceptibility.

• Received 2 July 1990

DOI:https://doi.org/10.1103/PhysRevB.42.10761