Experiments on nanostructured formed due to short-time annealing

Abstract

For technical applications the commonly used thermal processing of the amorphous alloy consists of one-hour anneals at about . This procedure leads to very soft magnetic properties due to the formation of the nanocrystalline Fe(Si) phase in the remaining amorphous matrix. In order to study the onset and development of the nanocrystalline phase the as-quenched amorphous samples were annealed in an Ar atmosphere at temperatures of and for different annealing times: 15 s, 30 s, 60 s, 90 s, 120 s, 180 s and 300 s. For sample characterization we used the conventional Mössbauer effect technique and additionally Mössbauer measurements in radiofrequency magnetic fields, which are very sensitive to magnetostriction and magnetic anisotropies. The measurements were supplemented with electron transmission microscopy and electron diffraction studies. Our short-time annealing experiments clearly show that in order to form good magnetically soft properties the annealing times of 1 - 2 min at and of only 15 - 30 s at are sufficient.