Published online by Cambridge University Press: 25 February 2011
The ability of neutron diffraction in determining the nature and extent of magnetic ordering is illustrated for the intermetallic compounds, Y6(Fe,Mn)23, and ErFe3. Substitution with other 3d transition metals influences the Fe-Fe exchange forces such as to alter, sometimes considerably, the magnetic properties, e.g., local site magnetic anisotropies in Er(Fe,Ni)3 and thermal expansion anomalies in the R2 (Fe,Co)14B compounds. When the 3d atoms are near neighbors in the periodic chart, their nuclear scattering lengths for neutrons are sufficiently different to permit the detection of preferential occupation of the several nonequivalent crystallographic 3d metal sites, i.e., atomic ordering, present in the R6M23, and R2Fe14B structures.