Controlled synthesis and magnetic properties of iron–cobalt–phosphide nanorods

Abstract

A simple one-step solution-phase synthesis of iron–cobalt–phosphide ((Fe_1−xCo_x)₂P) nanorods (NRs) is reported in this paper. Through the control of the amount of Co in the samples, the crystal structure of (Fe_1−xCo_x)₂P NRs changes from a pure Fe-rich hexagonal Fe₂P type structure to a mixture of Fe-rich hexagonal Fe₂P and Co-rich orthorhombic Co₂P type structures. These samples show superparamagnetic behavior at room temperature and ferromagnetic properties at 10 K. When the Co composition is 0.09, the (Fe_0.91Co_0.09)₂P sample has the highest coercivity around 5.74 kOe at 10 K. The current route provides a new and general chemical method for tunable preparation of (Fe_1−xCo_x)₂P (x < 0.28) NRs, which are significant for the development of new iron- or cobalt-rich permanent magnet materials without rare-earth or noble metals.