Magnetization of CeCu sub 6 at Low Temperatures

The heavy-fermion system (HFS) CeCu sub 6 shows no long-range magnetic order. However, antiferromagnetic (AF) correlations have been previously observed in inelastic neutron scattering (INS). High-accuracy magnetization measurements on a single crystalline sample at very low temperatures are reported, which show a metamagnetic-like transition in magnetic fields B ||c (orthorhombic notation). At T = 0.15K, the susceptibility chi sub c (B) = dM(B)/dB exhibits a distinct maximum at B = 1.7 T. This maximum remains at the same field with increasing temperature, but becomes weaker until it finally disappears around T = 0.9K. This new feature for CeCu sub 6 coincides with the field where the AF-correlated excitations in the INS disappear. This supports the idea that a metamagnetic-like transition is a common feature of "nonmagnetic" HFS, even if--as in the case of CeCu sub 6 --the AF-correlations are weak compared to local on-site fluctuations.