Theoretical study of the hyperfine field at Cu impurities diluted in an   iron host
  Magnetic hyperfine field at Cu isotopes as impurities in Fe were recently measured at low temperature. A model to explain these experimental results is proposed. The diluted Cu impurities in the ferromagnetic Fe host are described by an extension of the Daniel-Friedel model, including the next neighbor perturbation. In order to account for the available experimental data in Cu isotopes with atomic masses $A$ = 59, 67, 69 and 71 as impurity, we needed to incorporate the Cu anomaly volume in the effective charge to be screened and in the self-consistent procedures. 
A. L. de Oliveira, C. M. Chaves, N. A. de Oliveira and A. Troper
nucl-ex