title: Ferromagnetic quantum critical fluctuations in YbRh2(Si0.95Ge0.05)2.
abstract: The bulk magnetic susceptibility chi(T,B) of YbRh(2)(Si(0.95)Ge(0.05))(2) has been investigated close to the field-induced quantum critical point at B(c) = 0.027 T. For B < or= 0.05 T a Curie-Weiss law with a negative Weiss temperature is observed at temperatures below 0.3 K. Outside this region, the susceptibility indicates ferromagnetic quantum critical fluctuations, chi(T) proportional, variantT-0.6 above 0.3 K. At low temperatures the Pauli susceptibility follows chi(0) proportional, variant(B-B(c))(-0.6) and scales with the coefficient of the T(2) term in the electrical resistivity. The Sommerfeld-Wilson ratio is highly enhanced and increases up to 30 close to the critical field.
authors.affiliation: Max-Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Gegenwart
authors.forename: J
authors.initials: J
authors.lastname: Custers
authors.forename: Y
authors.initials: Y
authors.lastname: Tokiwa
authors.forename: C
authors.initials: C
authors.lastname: Geibel
authors.forename: F
authors.initials: F
authors.lastname: Steglich