Abstract
The crystallographic symmetry of antiferromagnetic CoO was studied using high-resolution synchrotron powder diffraction in the temperature range 10–300 K. The high-quality powder patterns unambiguously revealed a monoclinic symmetry (space group and allowed the extraction of accurate values for the lattice constants. The temperature dependence of the monoclinic deformation scales with the much stronger tetragonal distortion as determined from laboratory x-ray diffraction. Magnetic ordering is associated with a cubic-to-monoclinic transition that is, thus, of first order. Neutron powder-diffraction data are compatible with a collinear magnetic structure with the moments ordered in the monoclinic ac plane.
- Received 26 December 2000
DOI:https://doi.org/10.1103/PhysRevB.64.052102
©2001 American Physical Society