Metamagnetic behaviour in CeCu₆

The metamagnetic behaviour, which corresponds to one of the characteristic properties in the heavy fermion compounds, was studied by measuring the electrical resistivity under pressure and magnetic field for a typical heavy fermion compound CeCu₆ with orthorhombic structure. The transverse magnetoresistance at 100 mK indicated a peak structure at H_m = 20 kOe for the magnetic field H//c-axis under ambient pressure. H_m is found to increase linearly as a function of pressure and indicates H_m = 102 kOe at 1.75 GPa, for example. The quantum critical point is thus likely to exist at a slightly negative pressure value of ∼ 0.21 GPa from extrapolating H_m to zero. The ρ₀ and A values in the electrical resistivity ρ = ρ₀+AT² decrease steeply in magnitude with increasing pressure and magnetic field, indicating that the heavy fermion state is destroyed by pressure and magnetic field.