The magnetic hyperfine field at 181Ta impurities in the 4f-ferromagnets Ho and Er

The magnetic hyperfine field Hsub(hf) at 181Ta impurities in the ferromagnetic Rare Earth metals Ho and Er has been determined by time differential perturbed angular correlation measurements at 4.2 K. The results: [Hsub(hf)(TaHo)] = 101(8)kG, [Hsub(hf)(TaEr)] = 94(8)kG together with the previously determined values of Hsub(hf)(TaGd) and Hsub(hf)(TaDy) show that the magnetic hyperfine field at Ta impurities in the Rare Earth metals is predominantly due to the conduction electron polarization of the hosts. (orig.)