X-ray and neutron diffraction study of the holmium-iron system

Neutron diffraction and x-ray powder studies have been made of holmium-iron intermetallic compounds. The magnetic moments of Ho and Fe are in good agreement with measured spontaneous magnetization assuming a ferrimagnetic model with the Ho moments antiparallel to the Fe moments. The magnetic moments of the Fe atoms are found to be localized and thus independent of the rare earth content in the alloys. In contrast to HoCo₃, (00ℓ) type magnetic peaks in the neutron diffraction patterns are still prevalent at room temperature and gradually decrease as the Curie temperature is approached. This fact indicates that the easy direction of magnetization remains in the basal plane. The easy direction of magnetization at room temperature is found to be parallel with the cube edge in HoF₂ and to lie in the basal plane in HoFe₃ and Ho₂Fe₁₇. The easy direction is parallel to the a-axis in Ho₂Fe₁₇. It is parallel to the b-direction, i.e. 30º from an a-axis, in the HoFe₃ hexagonal cell --Abstract, page ii