%0 Journal Article
%A Chen, Xinfeng
%A Higashikozono, Soma
%A Ito, Keita
%A Jin, Lei
%A Ho, Ping-Luen
%A Yu, Chu-Ping
%A Tai, Nyan-Hwa
%A Mayer, Joachim
%A Dunin-Borkowski, Rafal E.
%A Suemasu, Takashi
%A Zhong, Xiaoyan
%T Nanoscale measurement of giant saturation magnetization in α″-Fe16N2 by electron energy-loss magnetic chiral dichroism
%J Ultramicroscopy
%V 203
%@ 0304-3991
%C Amsterdam
%I Elsevier Science
%M FZJ-2020-02975
%P 37 - 43
%D 2019
%X Metastable α″-Fe16N2 thin films were reported to have a giant saturation magnetization of above 2200 emu/cm3 in 1972 and have been considered as candidates for next-generation rare-earth-free permanent magnetic materials. However, their magnetic properties have not been confirmed unequivocally. As a result of the limited spatial resolution of most magnetic characterization techniques, it is challenging to measure the saturation magnetization of the α″-Fe16N2 phase, as it is often mixed with the parent α′-Fe8N phase in thin films. Here, we use electron energy-loss magnetic chiral dichroism (EMCD), aberration-corrected transmission electron microscopy, X-ray diffraction and macroscopic magnetic measurements to study α″-Fe16N2 (containing ordered N atoms) and α′-Fe8N (containing disordered N atoms). The ratio of saturation magnetization in α″-Fe16N2 to that in α′-Fe8N is determined to be 1.31 ± 0.10 from quantitative EMCD measurements and dynamical diffraction calculations, confirming the giant saturation magnetization of α″-Fe16N2. Crystallographic information is also obtained about the two phases, which are mixed on the nanoscale.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:30862364
%U <Go to ISI:>//WOS:000465021000005
%R 10.1016/j.ultramic.2019.02.016
%U https://juser.fz-juelich.de/record/878654