Crystallographic structure and magnetic properties of NdyDy1−yFe11−xTiCox compounds

A series of NdyDy1−yFe11−xTiCox compounds with y = 0, 0.2, 0.4, 0.6, 0.8, 1.0 and x = 0, 0.2, 0.4, 0.6, 0.8, 1.4, 1.8, 2.4 alloys were prepared by arc melting and studied by X-ray and neutron powder diffraction. Samples are found to crystallize in the ThMn12-type structure. The lattice parameter a, c and unit cell volume V of NdyDy1−yFe11−xTiCox increase linearly with increasing Nd substitution. The lattice parameters of Nd0.5Dy0.5Fe11−xTiCox compounds show some complexities with increasing Co content, where the lattice parameter c decreases with the substitution of Co for Fe while the lattice parameter a and unit cell volume V first increase a little and then decrease with increasing Co content. In NdyDy1−yFe11−xTiCox compounds, Ti atoms prefer to occupy the 8i sites and Co atoms prefer to occupy the 8j and 8f sites. Magnetic measurements show that the Curie temperature can be largely elevated by the substitution of Co for Fe.