Stress-induced magnetic anisotropy in Fe-based nanocrystalline alloy with addition of 1-5 at.% Cr

Magnetic properties and thermal stability of the nanocrystalline Fe(73.5-x)Cr(x)Si(13.5)B(9)Nb(3)Cu(1) (x = 0,1, 2, 3 and 5%) ribbons obtained by rapid quenching after thermal- and stress-annealing at 520 C were investigated with the aim to produce materials with new functional possibilities. In this study it is shown that in the alloys with 1 -5 at.% Cr, just as in Finemet alloy without Cr, a magnetic anisotropy can be induced in the course of stress-annealing and its easy magnetization axis is perpendicular to the direction of tensile stress, i.e. perpendicular to long side of ribbon. The curves of the magnetization reversal measured along the ribbon axis were inclined, indicating a constant value of a magnetic permeability in a wide range of magnetic fields. The results show that substitution of Fe for Cr improves the thermal stability of the alloy. The higher the Cr-content, the slower the process of the induced anisotropy reduction in the course of annealing at 520 degree C. Cr-containing iron-based nanocrystalline materials can be therefore proposed for the study as MI sensitive elements at enhanced temperatures.