Scientists from the National University of Singapore (NUS) have recently developed a magnetic sensor made from graphene and boron-nitride, which they say is about 200 times more sensitive than current commercially available silicon sensors.
Most home-based appliances such as washing machines and refrigerators are built with silicon sensors or semiconductors which can detect the change in an electrical resistance triggered by a magnetic field. This principle is known as magnetoresistance.
In several ways, the new magnetic sensor can perform better than usual semiconductors that were made of silicon and indium antimonide.
Optimized Sensor Characteristics
The new magnetic sensor is made up of a few sheets of carrier-moving networks that can be manipulated by a magnetic field. Researchers tested its efficacy with a different pairing material at various temperatures and different angles of magnetic field.
Dr. Kalon Gopinadhan from the NUS Nanoscience and Nanotechnology Institute explained that they first tried to understand how graphene responded under a magnetic field. The team discovered that the multilayer hybrid structure showed a large response with it.
The new magnetic sensor showed higher sensitivity to magnetic fields. When exposed to the temperature of 127 degrees Celsius or around 260 degrees Fahrenheit, the hybrid sensor increased in sensitivity by about eight times more compared to previous lab results. This makes the device ideal for high-temperature settings.
Researchers also said that these graphene multi-layers can be altered by tweaking the sensor's voltage, in turn optimizing the sensor's characteristics.
Graphene as an Effective Material
NUS Associate Professor Yang Hyunsoo, lead researcher of the study, explained that graphene as flexible carbon sheets are more sensitive than usual semiconductors. When combined with boron-nitride, graphene enables electrons to move very quickly in an interface.
"These electrons can thus respond to magnetic fields with greater sensitivity," said Professor Yang.
Using graphene as a material makes it effective for wearable technology, researchers said. Harvesting graphene costs much cheaper than silicon as well. The material can be found in cloth, insects and plants, and can be easily mined from graphite.
Industry Applications
The new magnetic sensor will mainly be applied in the automotive industry. The technology can be used in devices like car position sensors and interlocks, as well as flow meters. One problem that current silicon sensors used in cars have is that when the car's temperature changes, the sensor is affected, too.
Professor Yang added that the hybrid sensor can fill the performance gap of commercially-existing sensors. It may also even find its place in future thermal switches and hard drives.
Meanwhile, researchers say that the magnetoresistance industry will blow up to be worth US$2.9 billion within five years.
All these findings can be found in a report issued in the journal Nature Communications.
