The Kondo Effect in the Presence of Magnetic Impurities
  We measure transport through gold grain quantum dots fabricated using electromigration, with magnetic impurities in the leads. A Kondo interaction is observed between dot and leads, but the presence of magnetic impurities results in a gate-dependent zero-bias conductance peak that is split due to an RKKY interaction between the spin of the dot and the static spins of the impurities. A magnetic field restores the single Kondo peak in the case of an antiferromagnetic RKKY interaction. This system provides a new platform to study Kondo and RKKY interactions in metals at the level of a single spin. 
H. B. Heersche, Z. de Groot, J. A. Folk, L. P. Kouwenhoven, H. S. J.   van der Zant, A. A. Houck, J. Labaziewicz, I. L. Chuang