Highly oriented epitaxial (α′′+α′)-Fe16N2 films on α-Fe(001) buffered MgAl2O4(001) substrates and their magnetization

Soma Higashikozono, Keita Ito, Fumiya Takata, Toshiki Gushi, Kaoru Toko, Takashi Suemasu

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We grew epitaxial films of α′-Fe8N by molecular beam epitaxy on α-Fe buffered MgO(001) and MgAl2O4(MAO)(001) substrates. The lattice mismatches of these substrates with α′-Fe8N are −4.0% and 0.08%, respectively. We discuss effects on the crystal orientation of the grown layers in terms of the substrate material and the thickness of an α-Fe buffer layer. The 3-nm-thick α-Fe buffer layer on MAO was compressively strained and provided a more suitable in-plane lattice constant for growth of α′-Fe8N. The full width at half maximum of the x-ray ω-scan rocking curve peak intensity of the α′-Fe8N(002) plane was 0.09° when it was formed on α-Fe(3 nm)/MAO. This value was much smaller than that obtained for α-Fe(3 nm)/MgO samples (1.85°). (α′′+α′)-Fe16N2 films, which had partly ordered N-sites, were formed by post-annealing of the α′-Fe8N films on α-Fe/MgO(001) and α-Fe/MAO(001) at 165 °C. The degree of N-site ordering reached 0.08 after 20 h for (α′′+α′)-Fe16N2 grown on α-Fe(3 nm)/MAO(001). The saturation magnetizations were approximately 1650 emu/cm3, regardless of the annealing time and substrate used. The saturation field of the (α′′+α′)-Fe16N2 films increased by the post-annealing.

Original languageEnglish
Pages (from-to)691-695
Number of pages5
JournalJournal of Crystal Growth
Volume468
DOIs
Publication statusPublished - 2017 Jun 15

Keywords

  • A1. Magnetization
  • A3. Molecular beam epitaxy
  • B1. Iron nitride
  • B1. MgAlO

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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