Speaker
Description
In this work, we confirmed that reversible magnetization mechanisms also contribute to the hysteresis of the magnetizing reversal, and are accompanied with an energy loss, which was explained as originating from the frictional effects when local spins rotate. We modelled this hysteresis by calculating the area of the small hysteresis loops obtained by integrating of the reversible relative permeability measured along DC hysteresis loops (Fig. 1). This approach fills the gap, as many models neglect these effects and attribute the whole energy loss to irreversible magnetization, and the mentioned small hysteresis has until now been only commented qualitatively. Here, we quantified the energy dissipation coming from reversible magnetization for different representative Fe-based soft magnetic powder compacted and composite materials, under different magnetizing conditions of a DC magnetization cycle, and we found that different parameters lead to different percent proportions of the particular types of magnetization processes. Further analysis of these results led to a finding confirming theoretical assumption that the reversible rotations of magnetization vector are much more energy consuming than the reversible displacements of domain walls, hence the area of a hysteresis loop of the integrated reversible permeability approximately reflects the reversible magnetization vector rotations percentage within all magnetization processes. Such approach enables to quantify the proportions of reversible magnetization vector rotations solely, because the reversible permeability measurements reflect the portion of all reversible magnetization processes including the reversible domain wall displacements.
Fig. 1 The small hysteresis in reversible magnetization curves (obtained by integration of reversible permeability) observed in Fe-based powder compacted material at maximum induction 0.8 T (left) and 1.2 T (right), compared with DC hysteresis loops.
Acknowledgements
This work was realized within the frame of the project “FUCO” financed by the Slovak Research and Development Agency under the contract APVV-20-0072; and the Scientific Grant Agency of Ministry of Education of Slovak Republic and Slovak Academy of Sciences (project VEGA 1/0132/24).
