Rare-earth doped cobalt-based amorphous alloy wires with enhanced performance of GMI sensor

The pursuit of high-resolution and low-noise giant magnetoimpedance (GMI) sensors is paramount for weak magnetic field detection, hinging closely related to the intrinsic magnetic properties, especially for GMI effect, of core amorphous alloy wires (AAWs). While the doping of rare-earth (RE) elements is known to significantly affect the soft magnetic characteristics of amorphous alloys, its impact on the modulation of the GMI effect remains under-explored. This study addresses this gap by developing high-performance, multi-element RE-doped (Gd, Sm and Y) Co₆₈Fe₄Si_14.8B₁₀Cr₃-RE_0.2 AAWs through advanced microalloying and modified glass-coating techniques, achieving the remarkable GMI effect of 1128 % in GMI ratio and pT-level magnetic noise of 61pT/ Hz^0.5 @ 1 Hz. Systematic analysis reveals that the incorporation of Sm markedly enhances the thermal stability of AAWs, leading to a remarkable effect permeability of 22,472 in GMI ratio and 0.88 A/m in coercivity. Most notably, the GMI sensor based on Sm-doped AAWs exhibits extraordinarily pT-level magnetic noise This work demonstrates a successful strategy for enhancing GMI sensor capabilities through RE elements microalloying, establishing a foundation for next-generation sensors with unparalleled precision and operational efficiency.