Fe and N self-diffusion in amorphous FeN: A SIMS and neutron reflectivity study

Simultaneous self-diffusion measurements of Fe and N in amorphous Fe86N14Fe86N14 alloy using secondary ion mass spectroscopy (SIMS) are reported. In addition, neutron reflectivity (NR) was used to study the Fe self-diffusion in the same compound. The broadening of a tracer layer of 57Fe8615N14 sandwiched between Fe86N14Fe86N14 layers was observed by SIMS measurements after the annealing of films at different temperatures. A decay of the Bragg peak intensity after isothermal annealing was also observed in [Fe86N14/57Fe86N14]10 multilayers in NR. It was observed by SIMS measurements that Fe diffusion was about 2 orders of magnitude smaller than N, even though the structural relaxation times for Fe and N were almost identical. This is an important result, indicating that the relaxation time of diffusion is basically driven by the relaxation of the structure itself.