Metamagnetic Behavior and Effect of Pressure on the Electronic State in Heavy-Fermion Compound YbRh2Zn20

Abstract

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 YbRh2Zn20 with the cubic CeCr2Al20-type structure. The metamagnetic behavior was observed at Hm = 65 kOe for the magnetic field along the direction below Tχmax = 5.3 K, at which the temperature of the magnetic susceptibility indicates a broad maximum. The coefficient A of the T2 dependence of electrical resistivity ρ=ρ0 + AT2 and the electronic specific heat coefficient C/T possess a broad maximum at Hm. The metamagnetic field Hm is found to decrease with increasing pressure and to become zero at a critical pressure Pc ≃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, t...