A metastable hard magnetic phase in the crystallization process of the Fe75Si11B10Nb3Sn1 alloy

A very interesting characteristic of FeSiB based amorphous alloys is its soft magnetic behavior. Most of these alloys remains soft along the crystallization process up to the nucleation of the iron borides. Examples of this are the widely studied Finemet and the FeSiBSn. In this work the crystallization of Fe₇₆Si₁₁B₁₀Nb₃ and Fe₇₅Si₁₁B₁₀Nb₃Sn₁ is studied by means of X-ray diffraction, Mössbauer spectroscopy and coercive magnetic field measurements after one hour isothermal annealing at different temperatures. In the crystallization process of the latter alloy a hard magnetic phase appeared when the samples were annealed above 773 K. The soft magnetic behavior was recovered after annealing at 873 K. The hyperfine parameters as well as the X-ray diffraction patterns are reported.