Hyperfine fields on Hafnium nuclei in iron and gadolinium metal

The recoil implanation perturbed angular correlation technique, IMPACT, has been used to study the hyperfine interaction in¹⁸⁰Hf in iron and gadolinium. The perturbed angular correlation through the Coulomb excited 4⁺ state was used, thus minimizing the effect of quadrupole interactions. The effective hyperfine fields on Hf in iron and gadolinium are determined to have the same sign, negative, and magnitudes of (507±60) kOe and (304±31) kOe, respectively. Results are compared with values reported from several other experiments ostensibly measuring the same quantity. Problems inherent in the various experimental techniques are considered.