Structural and magnetic properties of (Fe1−xCox)3P compounds: experiment and theory

The structural and magnetic properties of (Fe1−xCox)3P compounds have been investigated by means of X-ray and neutron diffraction experiments, magnetization measurements and first-principles calculations. The saturation magnetization and the transition temperature of (Fe1−xCox)3P decrease with increasing Co concentration. The magnetic moments on the three non-equivalent metal sites are determined in detail by means of neutron diffraction experiments and first principles calculations which both show that the moments on the different sites have different magnitudes and they all decrease with increasing Co concentration. Results show that Co preferentially substitutes Fe on two of the metal sites. The complex behavior of the individual magnetic moments and the site preferences of Co substitution are discussed in terms of atomic radius, coordination numbers, and eigenvalue sums.