  Simultaneous measurement of self-diffusion of iron and nitrogen in amorphous
iron nitride (Fe86N14) using secondary ion mass spectroscopy (SIMS) technique
has been done. In addition neutron reflectivity (NR) technique was employed to
study the Fe diffusion in the same compound. The broadening of a tracer layer
of 57Fe8615N14 sandwiched between Fe86N14 layers was observed after isothermal
vacuum annealing of the films at different temperatures in SIMS measurements.
And a decay of the Bragg peak intensity after isothermal annealing was observed
in [Fe86N14/57Fe86N14]10 multilayers in NR. Strong structural relaxation of
diffusion coefficient was observed below the crystallization temperature of the
amorphous phase in both measurements. It was observed from the SIMS
measurements that Fe diffusion was about 2 orders of magnitude smaller compared
to nitrogen at a given temperature. The NR measurements reveal that the
mechanism of Fe self-diffusion is very similar to that in metal-metal type
metallic glasses. The structural relaxation time for Fe and N diffusion was
found comparable indicating that the obtained relaxation time essentially
pertain to the structural relaxation of the amorphous phase.
