Abstract
Understanding the relationship between the surface conditions and giant magneto-impedance (GMI) in Co-rich melt-extracted microwires is key to optimizing their magnetic responses for magnetic sensor applications. The surface magnetic domain structure (SMDS) parameters of ~45 μm diameter Co69.25Fe4.25Si13B13.5-xZrx (x = 0, 1, 2, 3) microwires, including the magnetic domain period (d) and surface roughness (Rq) as extracted from the magnetic force microscopy (MFM) images, have been correlated with GMI in the range 1–1000 MHz. It was found that substitution of B with 1 at. % Zr increased d of the base alloy from 729 to 740 nm while retaining Rq from ~1 nm to ~3 nm. A tremendous impact on the GMI ratio was found, increasing the ratio from ~360% to ~490% at an operating frequency of 40 MHz. Further substitution with Zr decreased the high frequency GMI ratio, which can be understood by the significant increase in surface roughness evident by force microscopy. This study demonstrates the application of the domain period and surface roughness found by force microscopy to the interpretation of the GMI in Co-rich microwires.
Highlights
Understanding the relationship between the surface conditions and giant magneto-impedance (GMI) in Co-rich melt-extracted microwires is key to optimizing their magnetic responses for magnetic sensor applications
Co-rich melt-extracted amorphous microwires have been recognized as an exciting magnetic material involved in various applications[1,2,3,4,5], including geomagnetic detection sensors[6], magnetic induction hyperthermia[7,8], and detection of magnetically labeled biomolecules[9]
One method is via magneto-optical Kerr effect (MOKE) microscopy[17], which is an optical technique that measures the change in polarization of light after it is reflected from the surface of a magnetic material
Summary
Understanding the relationship between the surface conditions and giant magneto-impedance (GMI) in Co-rich melt-extracted microwires is key to optimizing their magnetic responses for magnetic sensor applications. As it is well known, the longitudinal dc magnetization process of Co-rich amorphous microwires, especially near zero magnetic field, is mainly determined by domain wall movement and rotational magnetization The latter mechanism is closely related to high frequency magneto-impedance, since at frequencies below ~10 MHz, eddy currents damp domain wall motion[11]. The correlation of these measurements on Zr-substituted Co68.15Fe4.35Si12.25 B15.25-xZrx microwires (x = 0–3) has allowed us to address this issue, while giving good guidance on optimization of the high frequency GMI responses of Co-rich microwires for advanced sensor applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
