Magneto-electronic studies of anti-perovskites NiNMn 3 and ZnNMn 3 Zahid Ali a , M. Shafiq a , S. Jalali Asadabadi b , H.A. Rahnamaye Aliabad c , Imad Khan a , Iftikhar Ahmad a,⇑ a Center for Materials Modeling and Simulations, University of Malakand, Chakdara, Pakistan b Department of Physics, Faculty of Science, University of Isfahan, Hezar Gerib Avenue, Isfahan 81744, Iran c Department of Physics, Hakim Sabzevary University, Sabzevar, Iran article info Article history: Received 29 January 2013 Received in revised form 19 July 2013 Accepted 28 July 2013 Available online 12 September 2013 Keywords: Anti-perovskites Electronic band structure DFT Anti-ferromagnetism abstract Density functional theory is used to investigate the structural, electronic and magnetic properties of the anti-perovskites NiNMn 3 and ZnNMn 3 . The calculated structural parameters are found consistent with the experimental results. The spin-polarized calculations of the electronic properties show metallic nat- ure of these compounds. Furthermore the magnetic phase for each compound is optimized, which reveals that both of these compounds prefer anti-ferromagnetic phase. The calculated effective magnetic moments are also found consistent with the experimental values. The studies presented in this paper confirm the magnetoresistive nature of these compounds. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction The unique physical properties of the anti-perovskite com- pounds are very attractive for advance hybrid devices [1]. The anti-perovskite compounds have gained considerable attention because of their interesting physical properties derived from the relationship between magnetic properties and crystal lattice, such as magnetostriction [2], giant magnetoresistance (GMR) [3,4], low temperature coefficient resistivity (L-TCR) [1], negative thermal expansion (NTE) [5] and superconductivity at high temperature [6,7]. Mn-based anti-perovskite XAMn 3 series with X = Ga, Zn, Cu, Ge, Sn, Ni and A = N, C, B are metallic compounds with cubic structure and space group Pm-3m. In these compounds A-atom lies at the body-centered, Mn atoms are located on the face-centered, and X-atom occupies the corners of a unit cell [8]. A comparison of perovskite and anti-perovskite show that transition metal has six nearest neighbor oxygens in perovskite structure, while Mn atom has only two nearest neighbors (A-atoms) in the anti-perovskite structure [9]. In anti-perovskite compounds the oxygen atoms are replaced by transition metals (TM). In XAMn 3 , when cation-X and anion-A sites are replaced by different elements (X = Ga, Zn, Cu, Ge, Sn, Ni and A = N, C, B), an extended family of Mn-based anti-perovskites can be obtained [10]. Due to strong hybridization near Fermi level ANMn 3 (A = Ni, Zn, Sn, etc.) narrow bands are formed which depends on the number of valence electrons on A site, because A site atom makes the system itinerant at Fermi level [11]. These compounds show paramagnetic (PM) behaviour at high temperature and anti-ferromagnetic (AFM) or ferromagnetic (FM) at low temperatures [2,12]. The manganese nitride anti-perovskites have a number of advantages over other materials, where they are stable in air and mechanically hard as well as formed of economically cheaper materials such as Mn, Ni and Zn. Manganese nitrides are also metallic and have high electric and thermal conductivity [13]. Cubic anti-perovskite materials ANMn 3 (A = Ni and Zn) are similar to perovskite oxides [14]. Chu et al. [11] and Kim et al. [15] experimentally prepared the polycrystalline sample of ANMn 3 by mixing powder of Mn 2 N and pure A (A = Ni and Zn) in a bag filled with nitrogen gas potted in an evacuated quartz tube. They determined the cubic structure of the compound with a space group Pm-3m by the Rietveld refinement method using powder neutron diffraction data. Between 160 K and 266 K temperature the magnetic structure of NiNMn 3 is the combination of two triangular AFM structures C 4g and C 5g while below 160 K it exists in C 5g AFM structure [12,16] ZnNMn 3 show different magnetic structures and properties than NiNMn 3 . It changes from paramagnetic (PM) phase to AFM phase at lower temperature with triangular C 5g structure [17]. These compounds does not favor ferromagnetic phase; however similar to NiNMn 3 a direct transition from AFM to PM occurs with the increase in temperature [8,9]. The magnetic phase transition from AFM to PM in ZnNMn 3 occurs at 190 K [18] ZnNMn 3 some- times shows sudden and irregular increase of few percent in lattice volume at transition temperature from PM to AFM, which is called magneto-volume effect (MVE) [5,19]. The magnetic transitions are isostructural so that the crystal structure remains the same. 0927-0256/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.commatsci.2013.07.040 ⇑ Corresponding author. Tel.: +92 332 906 7866. E-mail addresses: dr.iftikhar@uom.edu.pk, ahma5532@gmail.com (I. Ahmad). Computational Materials Science 81 (2014) 141–145 Contents lists available at ScienceDirect Computational Materials Science journal homepage: www.elsevier.com/locate/commatsci