MAGNETIC-STRUCTURE OF GAMMA-MN(GA) ALLOYS WITH DISTORTED CUBIC LATTICES

gamma-Mn alloys containing Ga undergo a distortion from the face-cente red-cubic structure to the face-centered-tetragonal structure with c/a < 1 or c/a > 1, depending on composition. The face-centered-orthorhom bic structure also exists in a composition range between the two tetra gonal phases. The antiferromagnetic structures of these phases have be en determined by neutron-diffraction experiments. The tetragonal and o rthorhombic phases exhibit collinear and noncollinear moments, respect ively. The results are consistent with the theoretical prediction by J o et al.