Neutron diffraction and Mössbauer spectroscopy were used in order to study gallium site preference and hyperfine fields at the six iron sites in ${\mathrm{Nd}}_2$(${\mathrm{Fe}}_{1\mathrm{-}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$${)}_{14}$B alloys (x=0–0.15). Ga atoms have a strong preference to substitute for the Fe(${\mathrm{j}}_1$) and then the Fe(c) atoms. The assignments of the 6 Fe sites and the corresponding hyperfine field are tentatively the following: 344 (${\mathrm{j}}_2$), 325 (${\mathrm{k}}_2$), 306 (${\mathrm{j}}_1$), 294 (${\mathrm{k}}_1$), 286 (c), and 261 (e) kOe.

• Received 23 April 1990

DOI:https://doi.org/10.1103/PhysRevB.42.6697