title: Low temperature electron spin resonance of the Kondo ion in a heavy fermion metal: YbRh2Si2.
abstract: We report an electron spin resonance (ESR) study on single crystals of the heavy fermion metal YbRh2Si2 which shows pronounced non-Fermi liquid behavior related to a close antiferromagnetic quantum critical point. It is shown that the observed ESR spectra can be ascribed to a bulk Yb3+ resonance. This is the first observation of ESR of the Kondo ion itself in a dense Kondo lattice system. The ESR signal occurs below the Kondo temperature (T(K)) which thus indicates the existence of large unscreened Yb3+ moments below T(K). We observe the spin dynamics as well as the static magnetic properties of the Yb3+ spins to be consistent with the results of nuclear magnetic resonance and magnetic susceptibility.
authors: Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany.
authors: J
authors: J
authors: Sichelschmidt
authors: V A
authors: VA
authors: Ivanshin
authors: J
authors: J
authors: Ferstl
authors: C
authors: C
authors: Geibel
authors: F
authors: F
authors: Steglich