Eur. Phys. J. B (2022) 95: 14
https://doi.org/10.1140/epjb/s10051-021-00271-z

Regular Article - Solid State and Materials

Effect of oxygen contamination on structural and magnetic properties of MnPd bilayer grown on Fe/MgO(001): Ab initio study

¹ Centre for Atomic Molecular Physics and Quantum Optics (CEPAMOQ), Faculty of Science, University of Douala, P.O. Box 8580, Douala, Cameroon
² Groupe de Simulations Numériques en Magnétisme et Catalyse (GSMC), Faculté des Sciences et Techniques, Université Marien Ngouabi, PB 69, Brazzaville, République du Congo
³ Unité de Recherche en Nanomatériaux et Nanotechnologies, Institut National de Recherches en Sciences Exactes et Naturelles (IRSEN), Brazzaville, République du Congo
⁴ School of Physics and Earth Sciences, The Technical University of Kenya, PO Box 52428, 00200, Nairobi, Kenya
⁵ UFR de physique et d’ingénierie, 3 Rue de l’Université, 67000, Strasbourg, France

Received: 9 March 2021
Accepted: 20 December 2021
Published online: 20 January 2022

Abstract

We present a detailed study of oxygen contamination on the structural and magnetic properties for both Fe/MgO(001) substrate and MnPd bilayer grown on Fe/MgO(001) by using a plane wave self consistent field (PWscf) method based on DFT and DFT+U approaches, where a generalized gradient correction for exchange-correlation potential is taken into account. For the clean () bilayer grown on Fe/MgO(001) substrate, we have found that the c(2x2)-MnPd/c(2x2)-MnPd arrangement, where the magnetic moments of the Mn (Pd) atoms belonging to the surface and subsurface of 4.61 (0.05 ) and -4.03 (0.21 ), is lowest in energy than the c(2x2)-MnPd/p(1x2)-MnPd, p(1x2)-MnPd/MnPd-c(2x2) and p(1x2)-MnPd/p(1x2)-MnPd arrangements. A ripple is obtained at the surface (subsurface) plane. The contamination by O (1-ML coverage) on top for both Fe/MgO(001) and MnPd/Fe(100) multilayers increases interlayer distances between the surface and subsurface layers, with a preferential adsorption of oxygen atoms on the fourfold hollow sites when both DFT and DFT+U approaches are used. Similar magnetic ordering is obtained for Fe/MgO(001) and O/Fe/MgO(001) as well as for (MnPd)/Fe(100) and O/(MnPd)/Fe(001) sytems, where n=1-2, taking into account both approaches. The DFT+U approach produces an enhancement of the magnetic moments but does not modify the magnetic ground states of those systems. Here, we found that one half of oxygen atoms is pushed out-of-plane while the other half penetrates the MnPd (Fe) surface, giving rise to the MnO (FeO) oxide surface, in agreement with available experimental data.