Magnetic field sensors are everywhere in modern life, even though most people never notice them.
These tiny electronic components help detect movement, position, and distance, and are found in products ranging from smartphones and computer hard drives to car steering systems, security sensors, and smart packaging.
Billions of magnetic sensors are manufactured every year.
However, many of today’s magnetic sensors rely on materials such as nickel and cobalt.
While these materials perform well, they can create environmental and health concerns if electronic waste is not properly recycled.
Their production can also require energy-intensive manufacturing processes.
Researchers in Germany have now developed a more sustainable alternative using common, environmentally friendly materials.
Their new magnetic sensors are made primarily from iron, cellulose, starch, and other biocompatible substances.
According to the research team, the sensors can achieve levels of sensitivity comparable to some commercial magnetic sensors while offering significant environmental benefits.
The study was published in the journal Nature Communications.
The project was led by scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Their goal was to create a practical magnetic sensor using materials that are widely available, safer for the environment, and easier to recycle.
Iron was an obvious choice because it is abundant, inexpensive, and biocompatible. However, iron alone is not sensitive enough for many modern sensing applications. To solve this problem, the researchers created special particles with an iron core surrounded by a thin layer of iron oxide. These so-called core-shell particles improved the magnetic performance of the sensor.
“We have known about iron and cellulose for centuries,” said researcher Lin Guo. “The challenge was developing a sensor that could perform well using these sustainable materials.”
Another important feature of the new technology is how the sensors are manufactured. Instead of using traditional processes that often waste materials, the researchers produce the sensors through screen printing, a technique commonly used in the textile industry.
The sensor material is printed only where it is needed, reducing both material consumption and energy use. The approach also allows large numbers of sensors to be produced efficiently and at low cost.
The researchers paid special attention to what happens when the sensors reach the end of their useful life. The magnetic particles are embedded in a biodegradable mixture of cellulose and starch. A protective coating made from biocompatible polymers or natural materials such as beeswax shields the sensors from moisture and helps determine how long they remain functional.
By adjusting this protective layer, scientists can control the sensor’s lifespan for different applications. When the biodegradable materials eventually break down, the remaining material is mostly oxidized iron—essentially rust.
The technology has already been licensed for commercial use. Researchers believe it could be particularly useful in products that only need electronics for a limited period, such as smart packaging, disposable medical devices, and agricultural monitoring systems.
The team is now working on improving the technology further by developing longer-lasting protective coatings, exploring new biodegradable materials, and integrating the sensors into flexible electronic devices.
Their ultimate goal is to help create a new generation of electronics that perform well while leaving a much smaller environmental footprint.
