Neutron diffraction study of a Nd3Pd20Ge6 sample with three successive magnetic phase transitions

Low-temperature powder neutron diffraction experiments down to 100 mK were performed on an inhomogeneous Nd3Pd20Ge6 sample. The onset of magnetic orde r of the Nd moments on 8c site is found to split into two phase transitions with a dominant commensurate antiferromagnetic component (k(1) = [1, 1, 1] below T-N1 = 1.75 K) and an additional weak incommensurate perturbation (k (1i) = [tau, tau, tau], tau=0.79, below T-N1i = 1.40 K) The Nd moments on 4 a site remain disordered down to T-N2 = 0.58 K and align perpendicular to t he propagation vector k(2) = [0, 0, 1]. (C) 2000 Elsevier Science B.V. All rights reserved.