Magnetic properties of PrPdSb and NdPdSb compounds

Magnetometric and neutron diffraction measurements performed for PrPdSb and NdPdSb (hexagonal, LiGaGe-type crystal structure) indicate the absence of any long-range magnetic order in PrPdSb at 1.5 K and a sine-modulated order in NdPdSb described by the wave-vector k = \0.1418(4), 0, 0\, stable below the Neel point at 10 K. The magnetic moment of 2.51(6) mu(B) is localized on the Nd ion. Below T-tau = 5.8 K, additional magnetic reflections appear pointing at a square-modulated magnetic structure. The magnetic moment at 1.67 K is 3.16(5) mu(B). In both magnetic phases of NdPdSb the moments are parallel to the hexagonal c-axis.