Magnetic structure in the segregated phases Nd0.93MnO2.96

We report complete information on a structural model (involving two perovskite phases with a slight different chemical composition and magnetic ordering temperatures) that is introduced in order to interpret powder neutron diffraction (PND) and magnetic measurement on Nd0.93MnO2.96 manganites. The magnetic structure derived from PND data shows that the Mn magnetic sub-lattice for both phases become ordered below T-N = 80 K corresponding to a canted ferromagnet with a spin arrangement (Cx, Fy, 0). The Nd magnetic sub-lattice for both phases becomes polarized below T = 19 K having a unique ferromagnetic component parallel to the ferromagnetic component Fy of the Mn sub-lattice. Magnetic measurement can be interpreted considering that whereas the ferromagnetic components of Mn magnetic sub-lattice of both phases are antiferromagnetically coupled in the temperature range 19-80 K, they appear to be ferromagnetically coupled below 19 K. This change is accompanied by an abrupt reverse of the magnetization as a function of the temperature near 19 K. (C) 2009 Elsevier B.V. All rights reserved.