Magnetic-field-induced quantum critical point in YbPtIn and YbPt_0.98In single crystals

Detailed anisotropic (H‖ab and H‖c) resistivity and specific heat measurements were performed on on-line-grown YbPtIn and solution-grown YbPt_0.98In single crystals for temperatures down to 0.4 K and fields up to 140 kG; H‖ab Hall resistivity was also measured on the YbPt_0.98In system for the same temperature and field ranges. All these measurements indicate that the small change in stoichiometry between the two compounds drastically affects their ordering temperatures (T_ord≈3.4 K in YbPtIn and ∼2.2 K in YbPt_0.98In). Furthermore, a field-induced quantum critical point is apparent in each of these heavy fermion systems, with the corresponding critical field values of YbPt_0.98In (H_c^ab around 35–45 kG and H_c^c≈120 kG) also reduced compared to the analogous values for YbPtIn (H_c^ab≈60 kG and H_c^c>140 kG).