Nucleation of the paramagnetic phase in Fe–B systems during B+ and N+ implantation

Magnetic-to-paramagnetic phase transformation in Fe–B and Fe–B-N systems, prepared by means of successive boron and nitrogen implantations into iron films, has been studied using the methods of conversion electron Mössbauer spectroscopy (CEMS), and Auger electron spectroscopy (AES). Boron and nitrogen implantation was carried out in a dose range of 6×1016–2×1017 ions/cm2 with energy of 20 keV, and a mean current density of less than 1.5 μA/cm2 at room temperature. It was established that the threshold concentration of paramagnetic phase formation comprised a value of approximately 30 at.% of boron, or total boron and nitrogen concentration. The role of radiation damage in Fe–B and Fe–B–N systems, in the observed differences in nucleation and growth of paramagnetic phase in ion-implanted systems, as compared to liquid-quenched ones, was discussed.