The hyperfine interaction of gadolinium and holmium in cubic Ho: (Gd,Ce)Fe2 compounds

The low-temperature hyperfine parameters of the ferrimagnetic C15 intermetallic system Ho_0.03Ce_xGd_0.97-xFe₂ have been measured at Gd using the 87 keV γ-ray of ¹⁵⁵Gd and at Ho using spin echo nmr of ¹⁶⁵Ho. A linear decrease of the hyperfine field B_t with increasing x is observed, the slope being almost the same for both nuclei. The observed slope (dB_t/dx ? -37T) is nearly three times greater than that found for ¹⁵⁵Gd in the analogous H₀:(Y, Gd)Fe₂ system; this is attributed to the influence of the increased conduction electron density when trivalent lanthanide ions are replaced by Ce⁴⁺.