The Influence of Nb and Mo Content on the Magnetisation Process of Bulk Amorphous Alloys Based on Fe

The defects, present in ferromagnetic alloys with amorphous structure, have a major impact on the magnetic properties of these alloys. These defects are present in the forms of point and linear defects. There is no direct method allowing for their observation. However, the sensitivity of the magnetisation vector to the presence of all inhomogeneities gives the opportunity for indirect estimation of the type of defects and their volume, based on analysis of the initial magnetisation curve. The alloys studied within this work were produced by injection of each respective liquid alloy into a copper die. For the alloys obtained in this way, investigations into the structural and magnetic properties were performed. The structural analysis of the Fe-based bulk amorphous alloys was performed according to the Kronmüller theorem. Based on the results of the investigations, it was found that an increase in the Mo contribution (at the expense of Nb) effected decreases in the values of the saturation magnetisation and the stiffness parameter Dspf . In the region known as the “approach to the ferromagnetic saturation”, the magnetisation process of the investigated alloys is connected with the rotation of the magnetisation vector in the vicinity of quasi-dislocational dipoles. For the alloys with Mo content of 4 and 5 at.%, the presence of linear defects meeting the condition Ddip> lH was identified.