Suppression of the Kondo state in YbRh2Si2 by large magnetic fields

Abstract We present DC-magnetization, M ( B ), magnetostriction, Δ L ( B )/ L , and magnetoresistance ρ ( T , B ) measurements on high-quality single crystals of YbRh 2 Si 2 in magnetic fields up to 18 T and at temperatures down to 15 mK . At B ★ ≈9.5 T , both M ( B ) and Δ L ( B )/ L show pronounced changes of their slopes, indicative for a broadened phase transition. For fields above B ★ , the coefficient A of the Fermi liquid behavior Δ ρ = ρ 0 + A ( B ) T 2 is reduced to very small values, indicating the suppression of the Heavy Fermion state.