Speaker
Description
The asymmetrical GMI ratio dependences of the Co-based microwires recorded during slow magnetization reversal in the longitudinal magnetic field are analyzed in frame of the model of the core-shell domain structure. Considering that Co-based microwire with negative magnetostriction has circularly oriented spontaneous magnetization in the shell, but its narrow core is longitudinally magnetized, there is a transition region in which the vector of spontaneous magnetization must turn by an angle of 90°. During magnetization reversal of the core, the irreversible movement of the single domain wall (Barkhausen jump) is detected [1], which is also manifested by a jump in the asymmetrical double-peak GMI ratio dependences with the maximum value ($\Delta Z/Z$)$_{max}=260\%$ at $H=\pm 2.5$ A/m. Measurements in a Helmholtz coil, which created an additional dc magnetic field, revealed the asymmetrical two-peak behavior of the GMI ratio, corresponding to the rotation of magnetization in the shell after the displacement of domain walls in the core of the Co-based microwire. The achieved high sensitivity of GMI measurements to external dc magnetic field makes the investigated microwires very promising candidates for sensor applications.
Acknowledgements
This research was supported by the Slovak Research and Development Agency under contract No. APVV-16-0079, by VEGA grant No. 1/0350/24 from the Scientific Grant Agency of the Ministry for Education of the Slovak Republic, by the project “Support for the Research and Development Potential in the area of Transportation Vehicles” ITMS 2014+Code 313011T557 and by Foundation Volkswagen Slovakia Grant No. 085/15_RT.
References
[1] J. Kravčák and P. Vrábel, “Onset of Magnetization Reversal in Glass-covered Co-Si-B Microwires,” IEEE Transactions on Magnetics. Institute of Electrical and Electronics Engineers (IEEE), pp. 1–1, 2024. https://doi.org/10.1109/tmag.2024.3446451
