Metamagnetic Behavior and Effect of Pressure on the Electronic State in Heavy-Fermion Compound YbRh^sub 2^Zn^sub 20

We measured the magnetic susceptibility, high-field magnetization, magnetoresistance, specific heat, and Hall coefficient, together with the electrical resistivity under high pressures and magnetic fields, for the heavy-fermion compound YbRh...Zn... with the cubic CeCr...Al...-type structure. The metamagnetic behavior was observed at H... = 65 kOe for the magnetic field along the direction below T... = 5.3 K, at which the temperature of the magnetic susceptibility indicates a broad maximum. The coefficient A of the T... dependence of electrical resistivity ... and the electronic specific heat coefficient C/T possess a broad maximum at H... The metamagnetic field H... is found to decrease with increasing pressure and to become zero at a critical pressure P... ...5.2 GPa. Correspondingly, the A value increases drastically in magnitude, and the Fermi liquid relation is no longer satisfied at 5.2 GPa in zero magnetic field, implying a non-Fermi liquid state. On the other hand, at magnetic fields of H > 20 kOe, the low-temperature resistivity exhibits a T... dependence even at 5.2 GPa. The A coefficient decreases rapidly with increasing magnetic field. These results indicate that an electronic state at 5.2 GPa corresponds to the quantum critical point. (ProQuest: ... denotes formulae/symbols omitted.)