Single-crystal neutron diffraction studies on CeCu2Ge2 and CeCu1.9Ni0.1Ge2

Abstract

We have performed single-crystal neutron diffraction studies on CeCu2Ge2 and CeCu1.9Ni0.1Ge2 to get insight into the very unusual magnetic properties of these compounds. CeCu2Ge2 orders antiferromagnetically below T-N=4.15 K in an incommensurate sinusoidal amplitude modulated structure. CeCu1.9Ni0.1Ge2 shows two successive magnetic phase transitions at T-N1=3.65 K and T-N2=2.65 K, respectively. The corresponding magnetic structures are very similar to each other as well as to the magnetic structure of pure CeCu2Ge2. Based on the temperature dependence of the intensities of the principal magnetic reflections, the two magnetic phases seem to superimpose independently of each other.