Correlating structure with ferromagnetism in melt-spun Gd100−xFex

▶ Nanocrystalline Gd100−xFex alloys with Fe concentrations 0 ≤ x ≤ 40 have been prepared by melt spinning. ▶ X-ray diffraction and transmission electron microscopy show that the underlying structure consists of nanograins of Gd surrounded by a disordered boundary region containing both Gd and Fe. Thus, the Fe preferentially occupies the boundary regions. The volume fraction of the disordered phase increases as the Fe concentration increases. ▶ The magnetization at low temperature is dominated by the ferromagnetic Gd grains. At temperatures greater than the bulk Gd Curie temperature, the Gd100−xFex alloys (x < 40) exhibit non-zero coercivity. ▶ The high-temperature coercivity is attributed to Fe-rich magnetically correlated clusters within the boundary regions.