Spin-flip scattering in heavy-fermion alloys

We studied the s-d model of two magnetic impurities which are coupled via a RKKY interaction. The purpose of this work is to investigate the relative importance of the RKKY interaction in the heavy-fermion systems.; In addition to the known Kondo xlnT dependence of the electron lifetime from single impurity scattering, we found a x{dollar}sp2{dollar}/T dependence of the electron lifetime due to impurity pair scattering (where x is the impurity concentration). This leads to a resistance maximum at a characteristic temperature T{dollar}sb{lcub}rm M{rcub}{dollar}, which is linearly dependent on x. This theoretical prediction agrees with experimental results in several heavy-fermion alloys, such as (Ce{dollar}sb{lcub}rm x{rcub}{dollar}La{dollar}sb{lcub}rm 1-x{rcub}){dollar}Cu{dollar}sb2{dollar}Si{dollar}sb2{dollar}.; We extended our study to include an external magnetic field. The field is predicted to suppress both the Kondo lnT effect and the RKKY 1/T effect, in agreement with experimental magnetoresistance data for UBe{dollar}sb{lcub}13{rcub}{dollar}.