Magnetic behavior in commercial iron-silicon alloys controlled by the dislocation dynamics at temperatures below 420 K

A decrease of the temperature dependent coercive forces up to around 370 K is discovered in iron silicon alloys, both in quenched samples and in samples which were previously thermally treated to achieve the highest magnetic quality. Alloys of composition Fe-6 wt.% Si and Fe-3 wt.% Si are studied. This reduction in the coercive force is controlled by an increase in the mobility of the domain walls due to the increase in the dislocation’s mobility enhanced by the movement of vacancies. It is worthwhile to mention that this reduction in coercive force is only present at these slightly elevated temperatures which are markedly smaller than the usual annealing temperatures for heat treatment of iron silicon alloys while it disappears again at room temperature. Neutron thermodiffraction, magnetic hysteresis loops tracer and mechanical spectroscopy are used as experimental techniques. •Iron silicon alloys, Fe-6.0 wt% Si and Fe-3.1 wt% Si.•Decrease in the value of the coercive force in around 40% which develops up to 370 K.•Mobility of the domain walls controlled by the dislocation’s mobility.•Dislocation’s mobility enhanced by the movement of vacancies.