As a result of their versatility and possible applications, flexible magnetic sensors have gained popularity. This popularity is also due to their applications in major areas of flexible electronics, such as consumer electronics, healthcare, soft robotics, automotive engineering, and more.
A group of researchers from Bar-Ilan University and Ben-Gurion University has reported a giant leap of more than an order of magnitude improvement in the sensitivity of flexible magneto-resistive sensors, heralding new opportunities for flexible sensors in medical devices, soft robotics, and more. Image: A flexible magnetic sensor grown on a polyamide tape and graphs showing the EMN (effectively, the detectable magnetic field) in pT as a function of frequency when the sensor is flat, bent, and flat after being bent. The graphs demonstrate the capability to detect magnetic fields smaller than 200 pT. Image Credit: Spintronics and Nanomagnetism Laboratory headed by Prof. Klein, Department of Physics, Bar-Ilan University
They are extensively used for tasks like strain, navigation, pressure sensing, posture, and motion tracking. A major advantage of flexible sensors over rigid ones, as a result of their bendability, is their conformability to a broad range of surfaces, such as those that are soft and shaped irregularly.
But this benefit has arrived at a cost, as flexible magnetic sensors have displayed considerably inferior capability of detecting small magnetic fields, which helps restrict their potential use.
This might now change, as a research group from Bar-Ilan University and Ben-Gurion University has reported a huge leap of over an order of magnitude enhancement in the sensitivity of flexible magneto-resistive sensors.
The sensors, which appear to be elliptical and grown on a polyamide tape, have the potential to detect low-frequency magnetic fields below 200 pico-Tesla, which is over 200,000 times smaller compared to the Earth’s magnetic field.
These values are not only the best among all types of flexible magnetic sensors reported to date, but they also surpass those of many rigid counterparts.
Lior Klein, Professor, Department of Physics, Bar-Ilan University
Klein added, “The unprecedented sensitivity, accompanied by simple design, low cost, and remarkable flexibility, make these sensors particularly attractive for being integrated in the next generation of flexible electronic devices.”
Klein headed the research with Dr. Asaf Grosz from Ben Gurion University.
Journal Reference
Nhalil, H., et al. (2023) Flexible planar Hall effect sensor with sub-200 pT resolution Editor’s Pick. Applied Physics Letters. doi.org/10.1063/5.0156588.