Measuring magneto-impedance in ferromagnetic wires subjected to external stimuli such as magnetic field, tensile stress, and temperature
See the report in the file "Report_Multi-stage calibration for impedance measurements.pdf".
SUMMARY
This project explores the critical role of surface impedance in ferromagnetic wires, advancing the development of materials with highly specialized microwave properties for applications in sensors, metamaterials, and other high-frequency technologies. Ferromagnetic microwires exhibit unique magnetic anisotropy and conductive behaviours, which influence their interaction with electromagnetic fields, making their precise characterization essential for practical implementation in advanced systems. To address this need, we have developed a broadband impedance measurement technique capable of operating up to 15 GHz, offering a streamlined and accurate approach for analysing the electromagnetic properties of these materials. This method provides valuable insights into how ferromagnetic microwires respond under various frequencies, bridging the gap between material science and real-world applications.
A centrepiece of our work is the design of customized printed circuit board (PCB) cells, optimized to simplify and enhance measurement accuracy. These PCB cells are coupled with a multi-stage calibration process, which ensures that our data is both reliable and adaptable to a range of experimental conditions. This level of precision and flexibility allows for the exploration of surface impedance under external stimuli, such as magnetic field, mechanical stress, or temperature. Our approach not only simplifies the characterization process but also provides a versatile framework for tailoring ferromagnetic microwires to specific applications, from high-performance sensors to innovative metamaterials.
To support this experimental framework, our device control programs were initially developed in LabVIEW-2015, leveraging its robust capabilities for instrumentation control and data acquisition. However, as our experiments have evolved, we now favour Python for automation and experiment management. Python's flexibility, extensive libraries, and ease of integration with modern hardware have enabled us to streamline our workflows and enhance the customization of our experimental setups.
KEY CONTRIBUTIONS
Broadband Measurement Technique: Establishes a method for accurate impedance measurements up to 15 GHz, crucial for analyzing microwire-based composites.
PCB Calibration Cells: Develops PCB cells for precise impedance measurements, accounting for factors like temperature and mechanical stress.
Numerical Simulation Compatibility: Enables use of experimentally derived impedance values in computational simulations, supporting advanced material design.
Our efforts in stress-impedance measurements have been particularly recognized, earning us an award from the Zwick/Roell company during their international competition: https://www.zwickroell.com/news-events/news/academia-day-2019/#:~:text=world%2Dclass%20institutions.-,Winners%20of%20the%202018%20ZwickRoell%20Science%20Award,properties%20of%20miniaturized%20metal%20specimen. This accolade underscores the innovation and precision of our techniques in studying the complex interplay between mechanical stress and electromagnetic properties.