The magnetic structures of metallic samarium have been determined from neutron-diffraction data on a single crystal of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$. Anomalies in a number of physical properties of this metal at 106 and 13.8°K are associated with ordering of the moments on the hexagonal and cubic sites, respectively. The unusual form factor expected for a $4f^5$ configuration has been observed. Striking evidence for important conduction-electron polarization effects has been found.

• Received 10 October 1972

DOI:https://doi.org/10.1103/PhysRevLett.29.1468