Magnetic structure of the Laves phase compound TiFe₂

The magnetic structure of TiFe₂ which crystallizes with the C15 Laves phase structure has been determined from neutron diffraction measurements made on both single-crystal and polycrystalline samples. In the antiferromagnetic structure the Fe2 atoms in the (6h) sites with the same z coordinate are coupled ferromagnetically with the moments in successive layers alternately parallel and antiparallel to the c-axis. The Fe1 atoms which are in the (2a) sites are at an anti-centre of symmetry and carry no ordered moment. Magnetization measurements support this structure, giving a positive paramagnetic Curie temperature and showing the metamagnetic transition characteristic of ferromagnetically coupled sheets. Polarized neutron measurements indicate that in the antiferromagnetic phase the two types of Fe atom contribute almost equally to the susceptibility and suggest that the magnetic moment on the Fe1 atoms is only induced by the molecular field due to the aligned moment on the surrounding Fe2 atoms.