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

Limitation on the availability of rare earth elements have made it 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 -Fe16N2, whose giant magnetic moment has been predicted to be well above any other from conventional first principles calculations. Despite its great promise, the 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. -Fe, Fe2O3, Fe8N, Fe4N ) whose concentrations are difficult to detect by conventional x-ray diffraction. Moreover, 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 (~0.1g) 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 -Fe16N2.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [2] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Minnesota, Minneapolis, MN (United States)
  3. Advanced Materials Corp., Pittsburgh, PA (United States)
Publication Date:
OSTI Identifier:
1257902
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of The Minerals, Metals & Materials Society
Additional Journal Information:
Journal Volume: 68; Journal Issue: 6; Journal ID: ISSN 1047-4838
Publisher:
Springer
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR); Spallation Neutron Source
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS Fe16N2