Neutron diffraction study on the magnetic structure of (Fe0.70Co0.30)2P

Ferromagnetic compound (Fe0.70Co0.30)2P (Tc ∼ 450 K) has been studied by means of powder neutron diffraction at temperatures between 12 and 300 K. Rietveld analysis shows that the compound has Co2P type orthorhombic structure with all the atoms occupying 4c positions in Pnma space group. Positional parameters are quite close to those in Co2P. Cobalt atoms occupy the tetrahedral site with ∼95% preference. The compound, unlike Fe2P, is a non-collinear ferromagnet with moments orienting at ϑ = 45° and ϕ = 30° for tetrahedral MI site and ϑ = 15° and ϕ = 5° for pyramidal MII site. Average values of the magnetic moments at 12 K are 0.82(18)μB and 1.65(5)μB at the MI and MII sites, respectively. These values are much less than the corresponding ones in the hexagonal Fe2P.