Magnetic structure of CePd2Ge2 and Ce(Pd0.35Ni0.65)2Ge2

We have determined the magnetic structures of CePd2Ge2 and Ce(Pd0.35Ni0.65)2Ge2 by single-crystal neutron diffraction measurements. The structure of CePd2Ge2 consists of ferromagnetically ordered sheets that are stacked antiferromagnetically along the propagation vector k=(1/2,1/2, 0), with the moment parallel to k. The magnetic moment and the Néel temperature are m=0.84(9)μB and TN=5.0(1) K, respectively. The magnetic structure of Ce(Pd0.35Ni0.65)2Ge2 is similar but with a modulation of the moment in the c direction and k=(1/2, 1/2, ±δ), with δ=0.16(1). The moment and the Néel temperature are reduced to m=0.51(3)μB and TN=3.1(1) K.