ANTIPARALLEL ORDERING OF MN AND ND MAGNETIC-MOMENTS IN ND0.7BA0.3MNO3

The crystal and magnetic structures of the giant magnetoresistive comp ound Nd0.7Ba0.3MnO3 have been investigated by means of neutron powder diffraction. The nuclear structure remains orthorhombic within the tem perature range 1.5-300 K. As expected from the higher size of Ba-ion r adii, the buckling as well as the distortion of MnO6 octahedra are les s pronounced than in the parent compounds Nd(0.7)A'0.3MnO3 (A' = Ca, S r). At 1.5 K, we observe a ferromagnetic ordering of both Nd and Mn ma gnetic moments along the b-axis. However, Nd and Mn moments point in o pposite directions. The saturated magnetic moment of Mn ions is 3.45 m u(B), whereas the magnetic moment of Nd ions reaches 0.45 mu(B) at 1.5 K. The Curie temperatures are T-c(Mn) = 142 K and T-c(Nd) = 20 K. (C) 1998 Elsevier Science B.V. All rights reserved.