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, p repared by means of successive boron and nitrogen implantations into iron f ilms, has been studied using the methods of conversion electron Mossbauer s pectroscopy (CEMS), and Auger electron spectroscopy (AES). Boron and nitrog en implantation was carried out in a dose range of 6 x 10(16)-2 x 10(17) io ns/cm(2) with energy of 20 keV, and a mean current density of less than 1.5 mu A/cm(2) at room temperature. It was established that the threshold conc entration of paramagnetic phase formation comprised a value of approximatel y 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 c ompared to liquid-quenched ones, was discussed. (C) 2000 Elsevier Science S .A. All rights reserved.