Structural evolution and magnetic properties in Fe70Cr10B20 ribbons

The evolution of the magnetic properties of Fe₇₀Cr₁₀B₂₀ alloy, initially in amorphous state, is studied during the whole crystallization process, from room temperature to 800 °C. Neutron thermodiffraction has been used in order to follow all the structural changes that take place in the sample, including the appearance of tetragonal phases and polymorphic transformations. The formation of these tetragonal phases, with high magnetic anisotropy, leads to a degradation of the soft magnetic response. The study of the correlation between structure and magnetic response helps to optimize the composition and heat treatments in these materials for their application in sensor devices.