BARC/PUB/2018/0278

 
 

Competing ferromagnetic and anti-ferromagnetic interactions in iron nitride ζ-Fe2N

 
     
 
Author(s)

Rao, K. S.; Salunke, H. G.
(TPD)

Source

Journal of Magnetism and Magnetic Materials, 2018. Vol. 449: pp. 582-589

ABSTRACT

The paper discusses the magnetic state of zeta phase of iron nitride viz. ζ-Fe2N on the basis of spin polarized first principles electronic structure calculations together with a review of already published data. Results of our first principles study suggest that the ground state of ζ-Fe2N is ferromagnetic (FM) with a magnetic moment of 1:528μB on the Fe site. The FM ground state is lower than the antiferromagnetic (AFM) state by 8.44 meV and non-magnetic (NM) state by 191 meV per formula unit. These results are important in view of reports which claim that ζ-Fe2N undergoes an AFM transition below 10 K and others which do not observe any magnetic transition up to 4.2 K. We argue that the experimental results of AFM transition below 10 K are inconclusive and we propose the presence of competing FM and AFM superexchange interactions between Fe sites mediated by nitrogen atoms, which are consistent with Goodenough-Kanamori-Anderson rules. We find that the anti-ferromagnetically coupled Fe sites are outnumbered by ferromagnetically coupled Fe sites leading to a stable FM ground state. A Stoner analysis of the results also supports our claim of a FM ground state.

 
 
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