Hyperfine interaction study of (Fe1-xCox)3P compounds

The magnetic and ordering properties of (Fe1-xCox)(3)P (x=0, 0.1, 0.2, and 0.33) compounds have been studied by Fe-57 Mossbauer technique. These investigations show that Co preferentially substitutes Fe in two out of three metal sites. Variations of the magnetic hyperfine field and the isomer shift with Co content is presented. The fourfold symmetry of each of the metal sites are destroyed magnetically due to different magnetic dipolar contributions and electrically due to different local orientations of the principal axes of the electric field gradient tensor with respect to the easy axis of magnetization. This is explained based on the assumption that the magnetic moments lie in the basal plane.