Speaker
Description
Wide variety of soft magnetic materials find application as functional materials in magnetic sensors. The requirements for their properties vary, but low coercivity is always expected. Some sensors require high permeability, the others high linearity. Both alloys with small and large magnetostriction, and small and large saturation flux density are required. We will show several sensors developed in our laboratory which are based on improved magnetic materials.
-Commercially available integrated fluxgate sensors have cores made of sputtered permalloy. Using low-magnetostriction amorphous material with induced anisotropy may lower the sensor noise and improve its temperature stability [1].
-Novel nanocrystalline sandwich flake material VITROLAM by Vacuumschmelze has linear loop and large resistance to in-plane eddy currents. It was developed for contactless chargers, but it already has its first sensors application [2].
-Inkjet printing and $3$D printing are attractive methods for the deposition of sensor cores, but the permeability is limited [3].
-Nanocrystalline tapes with flat loop are preferred materials for current transformers. These transformers are resistant not only to DC currents, but also to external DC fields [4].
-New simulation models allow to design structures from arrays of millions of nanowires [5].
-Low-permeability linear magnetic core can increase the sensitivity of Rogowski coil by one order while keeping their excellent linearity [6].
-Microwires from improved CoFeSiB composition were developed for precise orthogonal fluxgate sensors. These sensors achieved noise level well below $1$ $\mathrm{pT/\sqrt{Hz}}$ at $1$ Hz, if the excellent temperature offset stability is not required [7].
Acknowledgements
This work was supported by GACR project 24-12705S Novel Magnetic Position Sensors.
References
[1] J J. Maier et al., “CMOS-based micro-fluxgate with racetrack core and solenoid coils,” Sensors and Actuators A: Physical, vol. 379. Elsevier BV, p. 115886, Dec. 2024. https://doi.org/10.1016/j.sna.2024.115886
[2] P. Ripka et al., “Flat Magnetic X–Y Alignment Sensor,” IEEE Sensors Letters, vol. 8, no. 7. Institute of Electrical and Electronics Engineers (IEEE), pp. 1–4, Jul. 2024. https://doi.org/10.1109/lsens.2024.3414375
[3] D. Hrakova et al., “Inkjet-printed Mn-Zn ferrite nanoparticle core for fluxgate,” Journal of Magnetism and Magnetic Materials, vol. 563. Elsevier BV, p. 170003, Dec. 2022. https://doi.org/10.1016/j.jmmm.2022.170003
[4] P. Ripka et al., “Effect of external DC field on current transformers with amorphous and nanocrystalline cores,” Journal of Magnetism and Magnetic Materials, vol. 563. Elsevier BV, p. 170019, Dec. 2022. https://doi.org/10.1016/j.jmmm.2022.170019
[5] P. Ripka et al., “Apparent permeability of ordered magnetically soft nanowire arrays,” AIP Advances, vol. 12, no. 3. AIP Publishing, Mar. 01, 2022. https://doi.org/10.1063/9.0000316
[6] V. Grim and P. Ripka, “Rogowski Coil With Ferromagnetic Powder Core,” IEEE Magnetics Letters, vol. 13. Institute of Electrical and Electronics Engineers (IEEE), pp. 1–4, 2022. https://doi.org/10.1109/lmag.2022.3143470
[7] M. Butta et al., “An Improved Composition of CoFeSiB Alloy for Orthogonal Fluxgates,” Sensors, vol. 22, no. 6. MDPI AG, p. 2162, Mar. 10, 2022. https://doi.org/10.3390/s22062162
