Phase Concentration Determination of Fe16N2 Using State of the Art Neutron Scattering Techniques

S. P. Bennett, M. Feygenson, Y. Jiang, B. J. Zande, X. Zhang, S. G. Sankar, J. P. Wang, V. Lauter

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Due to limitations on the availability of rare earth elements it is imperative that new high energy product rare earth free permanent magnet materials are developed for the next generation of energy systems. One promising low cost permanent magnet candidate for a high energy magnet is α″-Fe16N2, whose giant magnetic moment has been predicted to be well above any other from conventional first principles calculations. Despite its great promise, the α″ phase is metastable; making synthesis of the pure phase difficult, resulting in less than ideal magnetic characteristics. This instability gives way to a slew of possible secondary phases (i.e. α-Fe, Fe2O3, Fe8N, Fe4N, etc.) whose concentrations are difficult to detect by conventional x-ray diffraction. Here we show how high resolution neutron diffraction and polarized neutron reflectometry can be used to extract the phase concentration ratio of the giant magnetic phase from ultra-small powder sample sizes (~0.1 g) and thin films. These studies have led to the discovery of promising fabrication methods for both homogeneous thin films, and nanopowders containing the highest reported to date (>95%) phase concentrations of room temperature stable α″-Fe16N2.

Original languageEnglish (US)
Pages (from-to)1572-1576
Number of pages5
JournalJOM
Volume68
Issue number6
DOIs
StatePublished - Jun 1 2016

Bibliographical note

Funding Information:
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).

Funding Information:
This work was supported by the Scientific User Facilities Division, the Office of Basic Energy Sciences (BES), US Department of Energy (DOE), (S.P.B., V.L., M.F.). This work was supported in part by ARPA-E (Advanced Research Projects Agency. Energy) projects under Contract No. 0472-1595 and No. DE-AR0000645.

Publisher Copyright:
© 2016, The Minerals, Metals & Materials Society (outside the U.S.).

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