T. Komatsu et al., MOSSBAUER STUDY ON THE MAGNETIC STATE OF IRON PARTICLES IN FE-N AND FE-ZR-N SOFT-MAGNETIC THIN-FILMS, Journal of Materials Science, 30(21), 1995, pp. 5484-5489
The magnetic state of alpha-Fe particles and the behaviour of nitrogen
and zirconium during annealing in Fe96N4 and Fe85.6Zr7.6N6.8 magnetic
thin films have been studied by conversion electron Mossbauer spectro
scopy for Fe-57. The crystalline phases present in the Fe-N annealed f
ilms were alpha-Fe and gamma'-Fe4N, and those in the Fe-Zr-N annealed
films were alpha-Fe and ZrN. In the Fe-N films annealed below 300 degr
ees C, about 60% nitrogen is incorporated interstitially into alpha-Fe
and the rest is used for the formation of gamma'-Fe4N. In the Fe-N fi
lm annealed at 500 degrees C, almost all nitrogen participates in the
formation of gamma-Fe4N, leading to the grain growth of alpha-Fe parti
cles and an increase in coercive force. The values (291-325 kOe) of in
ternal magnetic field of iron sites in alpha-Fe in the Fe-Zr-N films a
re much smaller than that (333 kOe) of the iron site in pure alpha-Fe.
Even if the Fe-Zr-N films were annealed at 500-700 degrees C, some zi
rconium and nitrogen is still incorporated substitutionally and inters
titially into alpha-Fe, respectively. In particular, the substitutiona
l zirconium depresses the grain growth of alpha-Fe particles, perhaps
due to a chemical interaction between zirconium and iron.