Fabrication of Fe16N2 films by sputtering process and experimental investigation of origin of giant saturation magnetization in Fe16N2

Jian Ping Wang; Nian Ji; Xiaoqi Liu; Yunhao Xu; C. Sánchez-Hanke; Yiming Wu; F. M.F. De Groot; Lawrence F. Allard; Edgar Lara-Curzio

doi:10.1109/TMAG.2011.2170156

Fabrication of Fe₁₆N₂ films by sputtering process and experimental investigation of origin of giant saturation magnetization in Fe₁₆N₂

Jian Ping Wang, Nian Ji, Xiaoqi Liu, Yunhao Xu, C. Sánchez-Hanke, Yiming Wu, F. M.F. De Groot, Lawrence F. Allard, Edgar Lara-Curzio

Energy Science and Technology Directorat

Research output: Contribution to journal › Article › peer-review

76 Scopus citations

Abstract

We present a systematic study to address a longstanding mystery in magnetic materials and magnetism, whether there is giant saturation magnetization in Fe₁₆N₂ and why. Experimental results based on sputtered thin film samples are presented. The magnetism of Fe₁₆N₂ is discussed systematically from the aspects of material processing, magnetic characterization and theoretical investigation. It is observed that thin films with Fe₁₆N₂+Fe₈N mixture phases and high degree of N ordering, exhibit a saturation magnetization up to 2.68T at room temperature, which substantially exceeds the ferromagnetism limit based on the traditional band magnetism understanding. From X-ray magnetic circular Dichorism (XMCD) experiment, transport measurement and first-principle calculation based on LDA+U method, it is both experimentally and theoretically justified that the origin of giant saturation magnetization is correlated with the formation of highly localized 3d electron states in this Fe-N system. A large magnetocrystalline anisotropy for such a material is also discussed. Our proposed cluster+atom theory provides promising directions on designing novel magnetic materials with unique performances.

Original language	English
Article number	6187762
Pages (from-to)	1710-1717
Number of pages	8
Journal	IEEE Transactions on Magnetics
Volume	48
Issue number	5 PART 1
DOIs	https://doi.org/10.1109/TMAG.2011.2170156
State	Published - May 2012

Funding

The work was supported in part by the U.S. Department of Energy, Office of Basic Energy Sciences under contract No. DE-AC02-98CH10886, characterization facility of National Science Foundation the Minnesota MRSEC program under Award Number DMR-0819885, NSF NNIN program and University of Minnesota Supercomputing Institute. All the samples and testing experiments reported in this paper have been done before September 2009 (first report of our work at UMN MINT review 2009) based on above-mentioned financial support. The microscopy at HTML/ORNL was sponsored by U.S. DOE, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. The authors are grateful to the useful discussion with Drs. Valeria Lauter, Chengjun Sun, Hailemariam Ambaye, and Steve M Heald from DOE national labs (ORNL, ANL) and Profs. Jack Judy, Paul Crowell, and Randall Victora from the University of Minnesota.

Funders	Funder number
National Science Foundation
U.S. Department of Energy
Office of Energy Efficiency and Renewable Energy
Basic Energy Sciences	DE-AC02-98CH10886, DMR-0819885
Minnesota Supercomputing Institute, University of Minnesota

Keywords

FeN
X-ray magnetic circular dichorism
XMCD
giant saturation magnetization
high magnetic moment
magnetic head
permanent magnet

Access to Document

10.1109/TMAG.2011.2170156

Cite this

Wang, J. P., Ji, N., Liu, X., Xu, Y., Sánchez-Hanke, C., Wu, Y., De Groot, F. M. F., Allard, L. F., & Lara-Curzio, E. (2012). Fabrication of Fe₁₆N₂ films by sputtering process and experimental investigation of origin of giant saturation magnetization in Fe₁₆N₂. IEEE Transactions on Magnetics, 48(5 PART 1), 1710-1717. Article 6187762. https://doi.org/10.1109/TMAG.2011.2170156

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