Stability and Magnetic Properties of Nd6fe13x (X = Al, Si, Cu, Zn, and Ga)

6:13:1 RE-Fe-X ternary alloy exists in the grain boundary and the triple junction region of Nd-Fe-B, which has a non-negligible effect on the properties of Nd2Fe14B. Here, the structural and thermodynamic stability of Nd6Fe13X are systematically investigated using first-principles method. RE6Fe13X (RE = Pr, Nd, and Dy; X = Al, Si, Zn, and Ga) can be formed spontaneously with a negative value of formation energy, while Nd6Fe13Cu with the value of 0.73 eV. Moreover, we characterize the electron occupying states by partial density of states. Based on the comprehensive consideration of forming energy and magnetic moment, we propose that partial replacement of Nd atoms with Pr atoms can gradually reduce the formation energy and still maintain its original antiferromagnetic state. Our calculated results will provide theoretical guidance for optimizing growth and magnetical properties of Nd2Fe14B and for improving the efficiency of grain boundary diffusion process.