Peculiarities of the antiferromagnetism in CeCu2Si2

We report on a detailed investigation of the magnetism in A-type CeCu2Si2 by neutron scattering, thermodynamic and transport measurements. The linewidths of the magnetic peaks broaden well below the Neel temperature TN ≈ 800mK pointing to a finite domain size/correlation length. In contrast, within the resolution of the experiments the magnetic order is static. Complementary measurements of the electrical resistivity observed a superconducting transition at T< 450mK well below TN. However, no anomaly has been detected in heat capacity measurements. All results indicate that A-type single crystals exhibit parasitic superconductivity limiting the size of the antiferromagnetically ordered regions. The observed behavior can be understood by the slight off-stoichiometry of A-type CeCu2Si2.