Journal of Magnetism and Magnetic Materials 281 (2004) 221–226 Phase segregation in the hole-doped manganite Nd 0.93 MnO 2.96 : magnetic measurements and neutron diffraction N. Ihzaz a,b , H. Vincent a, *, G. Dezanneau a , H. Roussel a , J. Dhahri b , M. Oumezzine b a Laboratoire des Mat ! eriaux et du G ! enie Physique, ENS de Physique de Grenoble, BP 46, 38402 Saint-Martin d’H" eres Cedex, France b Laboratoire de Physico-Chimie des Mat ! eriaux, D ! epartement de Physique, Facult ! e des Sciences de Monastir, 5019 Monastir, Tunisia Received 8 January 2004; received in revised form 2 April 2004 Available online 25 May 2004 Abstract Lacunar-controlled Nd 0.93 MnO 2.96 orthorhombic perovskite prepared at 1200  C has been studied at low temperature. Magnetization measurements suggest the coexistence below 80 K of ferro- and antiferromagnetic interactions between Mn atoms as in the stoichiometric parent compound NdMnO 3 . Nevertheless, spontaneous magnetization curves obtained after sample cooling under a magnetic field of 500 Oe (FC) and without magnetic field (ZFC) reveal a much original behavior. Magnetization changes sign twice on ZFC curve; strong negative magnetization is observed below 19 K on FC curve. On the basis of neutron diffraction data, this behavior is interpreted by considering the coexistence of two perovskite phases having chemical compositions and magnetic ordering temperatures slightly different; ferromagnetic components in the clusters of both phases are antiferromagnetically coupled in the range 20–80 K. Ferromagnetic ordering at 19 K of Nd atoms is accompanied by a rearrangement of the Mn ferromagnetic components which become parallel in all the clusters. r 2004 Elsevier B.V. All rights reserved. PACS: 61.66.Fn; 75.50.Ee; 75.60.d Keywords: Rare-earth manganites; Magnetic properties; Neutron diffraction; Phase segregation 1. Introduction Doped manganites of the general formula R 1x A x MnO 3 , where R is a trivalent rare-earth and A is a divalent alkaline-earth, monovalent alkali metal or represents a deficiency in R- occupation number, have been extensively investi- gated because of their colossal magneto-resistance (CMR) effect which is a considerable subject in scientific studies due to its potential application [1–5]. Depending on the type and amount of doping, these materials exhibit a variety of phenomena, such as double-exchange (DE) and antiferromagnetic super-exchange (SE) interac- tions between Mn 3+ and Mn 4+ ions [6–9]. More ARTICLE IN PRESS *Corresponding author. Tel.: +33-476-82-63-29; fax: +33- 476-82-63-94. E-mail addresses: Nejib.Ihzaz@inpg.fr (N. Ihzaz), Henri.Vincent@inpg.fr (H. Vincent). 0304-8853/$ - see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jmmm.2004.04.108