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Title: Modification of structure and magnetic anisotropy of epitaxial CoFe₂O₄ films by hydrogen reduction

Abstract

Heteroepitaxial CoFe₂O₄ (CFO) thin films with different thicknesses were deposited on MgO (001) substrates. The as-deposited CFO films show a clear switching of magnetic anisotropy with increasing film thickness. The thinner films (<100 nm) show a perpendicular magnetic anisotropy due to the out-of-plane compressive strain. The thicker films exhibit an in-plane easy axis owing to the dominating shape anisotropy effect. The magnetostriction coefficient of CFO films is estimated to be λ[001] =-188 × 10⁻⁶. Metallic CoFe₂ films were obtained by annealing the as-deposited CFO films in forming gas (Ar 93% + H₂ 7%) at 450 °C. XRD shows that CoFe₂ films are textured out-of-plane and aligned in-plane, owing to lattice matching between CoFe₂ and MgO substrate. TEM results indicate that as-deposited films are continuous while the annealed films exhibit a nanopore mushroom structure. The magnetic anisotropy of CoFe₂ films is dominated by the shape effect. The results demonstrate that hydrogen reduction can be effectively used to modify microstructures and physical properties of complex metal oxide materials.

Authors:
ORCiD logo [1];  [2];  [1];  [2];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Center for Integrated Nanotechnologies (CINT)
  2. Univ. of Texas, Arlington, TX (United States). Dept. of Physics
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1193448
Report Number(s):
LA/UR-15-20894
Journal ID: ISSN 0003-6951; APPLAB
Grant/Contract Number:  
AC52-06NA25396; W911NF-11-1-0507
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 106; Journal Issue: 11; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; magnetic anisotropy; magnetic films; epitaxy

Citation Formats

Chen, Aiping, Poudyal, Narayan, Xiong, Jie, Liu, J. Ping, and Jia, Quanxi. Modification of structure and magnetic anisotropy of epitaxial CoFe₂O₄ films by hydrogen reduction. United States: N. p., 2015. Web. doi:10.1063/1.4915504.
Chen, Aiping, Poudyal, Narayan, Xiong, Jie, Liu, J. Ping, & Jia, Quanxi. Modification of structure and magnetic anisotropy of epitaxial CoFe₂O₄ films by hydrogen reduction. United States. doi:10.1063/1.4915504.
Chen, Aiping, Poudyal, Narayan, Xiong, Jie, Liu, J. Ping, and Jia, Quanxi. Mon . "Modification of structure and magnetic anisotropy of epitaxial CoFe₂O₄ films by hydrogen reduction". United States. doi:10.1063/1.4915504. https://www.osti.gov/servlets/purl/1193448.
@article{osti_1193448,
title = {Modification of structure and magnetic anisotropy of epitaxial CoFe₂O₄ films by hydrogen reduction},
author = {Chen, Aiping and Poudyal, Narayan and Xiong, Jie and Liu, J. Ping and Jia, Quanxi},
abstractNote = {Heteroepitaxial CoFe₂O₄ (CFO) thin films with different thicknesses were deposited on MgO (001) substrates. The as-deposited CFO films show a clear switching of magnetic anisotropy with increasing film thickness. The thinner films (<100 nm) show a perpendicular magnetic anisotropy due to the out-of-plane compressive strain. The thicker films exhibit an in-plane easy axis owing to the dominating shape anisotropy effect. The magnetostriction coefficient of CFO films is estimated to be λ[001] =-188 × 10⁻⁶. Metallic CoFe₂ films were obtained by annealing the as-deposited CFO films in forming gas (Ar 93% + H₂ 7%) at 450 °C. XRD shows that CoFe₂ films are textured out-of-plane and aligned in-plane, owing to lattice matching between CoFe₂ and MgO substrate. TEM results indicate that as-deposited films are continuous while the annealed films exhibit a nanopore mushroom structure. The magnetic anisotropy of CoFe₂ films is dominated by the shape effect. The results demonstrate that hydrogen reduction can be effectively used to modify microstructures and physical properties of complex metal oxide materials.},
doi = {10.1063/1.4915504},
journal = {Applied Physics Letters},
issn = {0003-6951},
number = 11,
volume = 106,
place = {United States},
year = {2015},
month = {3}
}

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Works referenced in this record:

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    Works referencing / citing this record:

    Metal Oxide Nanocomposites: A Perspective from Strain, Defect, and Interface
    journal, October 2018