Magnetic structures of some strongly correlated electron Ce-Ni-Ge systems

Extending our study on the characterisation of the magnetic properties of the ternary germanides based on cerium and nickel, we have performed magnetisation measurements and neutron powder diffraction on CeNiGe3. The antiferromagnetic structure of this compound is dependent on temperature: (i) for T between TN=5.9(2) and 5.0(2) K, the magnetic peaks are associated with the k1=(1 0 0) propagation vector; (ii) below 5.0(2) K, the two propagation vectors k1=(1 0 0) and k2=(0 0.409(1) 1/2) coexist, but the intensities of the magnetic peaks corresponding to k1 decrease with temperature below 4.1(2) K. We discuss this complex magnetic behaviour in relation to the magnetic structure reported for Ce3Ni2Ge7. (orig.)