Large Linear Giant Magneto-Impedance Response of Microwire Annealed under Liquid Medium for Potential Sensor Applications

Abstract

Herein, we have presented the giant magneto-impedance (GMI) effect, microstructure and surface domain structure of the Co-Fe-based amorphous microwires after liquid medium—anhydrous ethanol Joule annealing (AJA). The AJA technique can effectively release the radial stress and induce large a circumferential magnetic field by changing the Joule heat transfer and the circumferential domain, to further tune the GMI performance of microwire. The linear response fields (0~3.5 Oe), the high sensitivity of 124.1%/Oe and the high GMI ratio make the microwire as promising materials for the miniaturized GMI sensors. The GMI ratios of [ΔZ/Z0]max(%) and [ΔZ/Zmax]max(%) increase the near-linearly to 201.9% and 200.5%, respectively, for the 250 mA anhydrous ethanol Joule annealed wires. Moreover, a linear response to Hex (ranging from 3.5 to 25 Oe, or more) is observed, which bears the potential in fabricating bi-sensors.

Highly Sensitive Detection of Weak Low Frequency Magnetic Fields Using Single Nanoscale Orthogonal MgO Magnetic Tunnel Junctions under a Large Bias Field

“…Thus detection of weak low frequency magnetic fields is crucial. 1,2) There are numerous low-field magnetic sensors that have been investigated for use in biosensors including coil-based sensors, 3,4) direct-current superconducting quantum interference devices (dc SQUIDs), 2,5,6) fluxgate magnetometers, [7][8][9] giant magneto-impedance sensors, [10][11][12] Hall effect sensors [13][14][15] and recently frequency-based sensors, [16][17][18] and magnetoresistive (MR)-based sensors. 1,[19][20][21][22] Above all others, MR-based sensors offer significant advantages: (i) MR sensors have an inherent advantage in size and power when compared to coil-based, fluxgate, and more complicated low-field sensing techniques such as SQUID and spin resonance magnetometers; 19) (ii) the technique used for fabricating MR sensors is a well-established technology for information storage which is CMOS compatible, large-scale, and cost-effective to produce; (iii) MR sensors also provide high sensitivity, adjustable detected field range, and room temperature (RT) operation.…”

Application of Ferromagnetic Microwires as Temperature Sensors in Measurements of Thermal Conductivity

“…Among them, the Joule annealing method has been widely used. A proper Joule heating current amplitude can effectively improve the soft magnetic properties of the microwires [9][10][11]. It was demonstrated that Co-rich amorphous microwires can be used to create a number of miniature sensors for measuring mechanical stresses, magnetic fields, temperature, etc.…”