Crystal and magnetic structures of Nd2Ni2Sn and Dy2Ni2Sn compounds

Neutron diffraction and magnetometric measurements on polycrystalline sampl es of Nd2Ni2Sn and Dy2Ni2Sn compounds: were performed in the temperature ra nge between 1.5 and 293 K. Both compounds have the orthorhombic crystal str ucture similar to the W2CoB2-type. In both compounds at T=1.5 K the rare ea rth moments form noncollinear magnetic structures with ferro- and antiferro -components. With increasing temperature changes from the noncollinear magn etic structure to a ferromagnetic one for Nd2Ni2Sn at 15 K and to an antife rromagnetic one for Dy2Ni2Sn at 28.1 K are observed. The transition to the paramagnetic state appears at 19.5 and 49.4 K for Nd2Ni2Sn and Dy2Ni2Sn, re spectively. (C) 1999 Elsevier Science S.A. All rights reserved.