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Title: Increased magnetic moment induced by lattice expansion from α-Fe to α′-Fe{sub 8}N

Abstract

Buffer-free and epitaxial α-Fe and α′-Fe{sub 8}N{sub x} thin films have been grown by RF magnetron sputtering onto MgO (100) substrates. The film thicknesses were determined with high accuracy by evaluating the Kiessig fringes of X-ray reflectometry measurements allowing a precise volume estimation. A gradual increase of the nitrogen content in the plasma led to an expansion of the iron bcc unit cell along the [001] direction resulting finally in a tetragonal distortion of about 10% corresponding to the formation of α′-Fe{sub 8}N. The α-Fe lattice expansion was accompanied by an increase in magnetic moment to 2.61 ± 0.06μ{sub B} per Fe atom and a considerable increase in anisotropy. These experiments show that—without requiring any additional ordering of the nitrogen atoms—the lattice expansion of α-Fe itself is the origin of the increased magnetic moment in α′-Fe{sub 8}N.

Authors:
; ;  [1];  [1];  [2]
  1. Institute of Materials Science, Technische Universität Darmstadt, 64287 Darmstadt (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
22402982
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; BCC LATTICES; EPITAXY; EXPANSION; IRON; IRON NITRIDES; MAGNESIUM OXIDES; MAGNETIC MOMENTS; NITROGEN; SPUTTERING; SUBSTRATES; THIN FILMS

Citation Formats

Dirba, Imants, E-mail: dirba@fm.tu-darmstadt.de, Komissinskiy, Philipp, Alff, Lambert, E-mail: alff@oxide.tu-darmstadt.de, Gutfleisch, Oliver, and Fraunhofer-Projektgruppe für Wertstoffkreisläufe und Ressourcenstrategie IWKS, 63457 Hanau. Increased magnetic moment induced by lattice expansion from α-Fe to α′-Fe{sub 8}N. United States: N. p., 2015. Web. doi:10.1063/1.4919601.
Dirba, Imants, E-mail: dirba@fm.tu-darmstadt.de, Komissinskiy, Philipp, Alff, Lambert, E-mail: alff@oxide.tu-darmstadt.de, Gutfleisch, Oliver, & Fraunhofer-Projektgruppe für Wertstoffkreisläufe und Ressourcenstrategie IWKS, 63457 Hanau. Increased magnetic moment induced by lattice expansion from α-Fe to α′-Fe{sub 8}N. United States. doi:10.1063/1.4919601.
Dirba, Imants, E-mail: dirba@fm.tu-darmstadt.de, Komissinskiy, Philipp, Alff, Lambert, E-mail: alff@oxide.tu-darmstadt.de, Gutfleisch, Oliver, and Fraunhofer-Projektgruppe für Wertstoffkreisläufe und Ressourcenstrategie IWKS, 63457 Hanau. Thu . "Increased magnetic moment induced by lattice expansion from α-Fe to α′-Fe{sub 8}N". United States. doi:10.1063/1.4919601.
@article{osti_22402982,
title = {Increased magnetic moment induced by lattice expansion from α-Fe to α′-Fe{sub 8}N},
author = {Dirba, Imants, E-mail: dirba@fm.tu-darmstadt.de and Komissinskiy, Philipp and Alff, Lambert, E-mail: alff@oxide.tu-darmstadt.de and Gutfleisch, Oliver and Fraunhofer-Projektgruppe für Wertstoffkreisläufe und Ressourcenstrategie IWKS, 63457 Hanau},
abstractNote = {Buffer-free and epitaxial α-Fe and α′-Fe{sub 8}N{sub x} thin films have been grown by RF magnetron sputtering onto MgO (100) substrates. The film thicknesses were determined with high accuracy by evaluating the Kiessig fringes of X-ray reflectometry measurements allowing a precise volume estimation. A gradual increase of the nitrogen content in the plasma led to an expansion of the iron bcc unit cell along the [001] direction resulting finally in a tetragonal distortion of about 10% corresponding to the formation of α′-Fe{sub 8}N. The α-Fe lattice expansion was accompanied by an increase in magnetic moment to 2.61 ± 0.06μ{sub B} per Fe atom and a considerable increase in anisotropy. These experiments show that—without requiring any additional ordering of the nitrogen atoms—the lattice expansion of α-Fe itself is the origin of the increased magnetic moment in α′-Fe{sub 8}N.},
doi = {10.1063/1.4919601},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}