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Description
Microwire sensing technology offers unique capabilities, including the ability to measure temperature at two distinct points using a single sensor without repositioning. This dual-point measurement is based on domain wall propagation from both ends of the glass-coated microwire, as the switching field value is influenced by the local temperature at the de-pinning centre, where the domain wall motion begins [1].
The domain structure of glass-coated magnetically bistable microwires can be simplified into three domains separated by two domain walls. The closure domain expands during remagnetization while the corresponding domain wall propagates along the microwire [2]. A temperature difference between the microwire's ends results in varying switching field values required for re-polarization.
A magnetic field gradient with decreasing intensity along the microwire’s axis must be established to enable effective measurement, requiring two excitation coils or a single coil with adjustable positioning. However, only one sensing coil is sufficient to detect the microwire’s response, making this approach efficient for contactless thermal sensing applications.
Acknowledgements
This work was partially supported by the projects APVV-16-0079 and VEGA-1/0180/23.
References
[1] V. Zhukova et al., “Review of Domain Wall Dynamics Engineering in Magnetic Microwires,” Nanomaterials, vol. 10, no. 12. MDPI AG, p. 2407, Dec. 01, 2020. https://doi.org/10.3390/nano10122407
[2] M. Al Ali et al., “Application of bistable glass-coated microwire for monitoring and measuring the deformations of metal structural members,” Measurement, vol. 208. Elsevier BV, p. 112458, Feb. 2023. https://doi.org/10.1016/j.measurement.2023.112458
