ANTIFERROMAGNETIC STRUCTURE IN COO

Possible magnetic structures of CoO, which is known to be the second k ind of antiferromagnet, are discussed for the cubic phase on the basis of the extended Hubbard model including the 3d spin-orbit coupling an d the intra-atomic full 3d-3d multipole interaction in the framework o f the Hartree-Fock (HF) approximation. In addition to a collinear sing le-Q structure; a noncollinear quadruple-Q one, both of which are comp atible with the neutron diffraction experiment, are obtained as stable HF solutions. The magnitude of the Co orbital magnetic moment is show n to be as large as similar to 1 mu(B).