Influence of a magnetic field applied during the quenching process on the spin density and nanoscale structure of an amorphous Fe-B ribbon

Abstract

The application of a magnetic field to the melt in the transverse direction of the wheel rotation during the solidification process induces magnetic anisotropy in amorphous magnetic ribbons. This procedure is here applied to a FeB amorphous alloy in order to check their influence on local electronic and nanoscale structure by comparing two samples (as quenched without field and field quenched). The existence of magnetic domains was showed via the Bitter technique. Mössbauer spectra analysis confirms an increase in the spin density (from 28 to 48%) in the applied field direction for the field quenched ribbon. Positron lifetime spectra analysis determines that at room temperature there is no influence on the nanoscale structure, but the annealing at 300 °C provokes the beginning of the nanocrystallization process in the field quenched sample while the samples as quenched without field remain fully amorphous.