Publication Date:
2014-12-19
Description:
We present an effective approach to improve the sensitivity of inductance coil sensors by designing a sensor core that consists of multiple soft ferromagnetic microwires. A systematic study of the longitudinally excited magneto-inductive (LEMI) effect has been performed in a non-magnetic copper wire coil with a filler composed of multiple Co-rich amorphous microwires. Melt-extracted microwires of Co 68.2 Fe 4.3 B 15 Si 12.5 and glass-coated microwires of Co 68 B 15 Si 10 Mn 7 with excellent soft magnetic properties were used for this study. We have shown that the LEMI ratio and field sensitivity of an inductive coil depend strongly upon the filler-to-air ratio inside the coil, the magnetic softness, and the anisotropy axis distribution of the microwire. Relative to a single-microwire based sensor, the LEMI ratio and field sensitivity of a multi-microwire based sensor are enhanced by three to four times, when varying the number of microwires inside the inductive coil. The sensitivity of the sensor using four glass-coated Co 68 B 15 Si 10 Mn 7 microwires in the core reaches a maximum value of 1957%/Oe. Our study paves a pathway for the development of novel room-temperature electric contact free magnetic sensors for use in industry, biomagnetism, space science, and geoscience.
Print ISSN:
0021-8979
Electronic ISSN:
1089-7550
Topics:
Physics
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