THE SOLID-SOLUTION ND2-XYXBANIO5, A PROGRESSIVE TRANSITION FROM A TRIDIMENSIONAL TO AN UNIDIMENSIONAL ANTIFERROMAGNETIC STATE

The solid solution Nd2-xYxBaNiO5 (0≤x≤2) was prepared and investigated by X-ray diffractometer. These compounds crystallize with orthorhombic symmetry, space group: Immm, Z=2 (a ≈ 3.8 A ̊, b ≈ 5.8 A ̊, c ≈ 11.5 A ̊). They are of Ln2BaNiO5 type. The replacement of neodynium by smaller yttrium ions leads to a compression of the NiO6 octahedra along ā. The study of the magnetic susceptibility vs temperature shows a progressive transition from a tridimensional to an unidimensional antiferromagnetic state for these oxides. The Neel temperatures are ranging from 7 to 20 K for 0 ≤ x < 1.9. © 1990.