Heat capacity, resistivity, thermoelectric power, and magnetic susceptibility studies are reported for single crystals of ${\mathrm{V}}_7$${\mathrm{O}}_{13}$ obtained by chemical-vapor-transport techniques. The entropy change accompanying magnetic ordering effects at 43.5 K is well below the values calculated on the basis of charge differentiation. Electrical and susceptibility anomalies are in accord with theoretical predictions for the prevalence of antiferromagnetic order below 43.5 K. A change in sign of the Seebeck coefficient as well as sharply dropping resistivity with decreasing temperature below the Néel temperature suggests the presence of two bands at the Fermi energy.

• Received 22 June 1981

DOI:https://doi.org/10.1103/PhysRevB.25.1703