A new hybrid magnetic sensor that is over 200 times more sensitive than most commercially available sensors has been developed by scientists, including those of Indian-origin.
The technological breakthrough hails opportunities for the development of smaller and cheaper sensors for various fields such as consumer electronics, information and communication technology, biotechnology and automotive.
When an external magnetic field is applied to certain materials, a change in electrical resistance, also known as magnetoresistance, occurs as the electrons are deflected.
The discovery of magnetoresistance paved the way for magnetic field sensors used in hard disk drives and other devices, revolutionising how data is stored and read.
In the search for an ideal magnetoresistance sensor, researchers have prized the properties of high sensitivity to low and high magnetic fields, tunability, and very small resistance variations due to temperature.
The new hybrid sensor developed by a team led by Associate Professor Yang Hyunsoo from National University of Singapore (NUS) may finally meet these requirements.
The sensor, made of graphene and boron nitride, comprises a few layers of carrier-moving channels, each of which can be controlled by the magnetic field.
The researchers characterised the new sensor by testing it at various temperatures, angles of magnetic field, and with a different pairing material.
"We started by trying to understand how graphene responds under the magnetic field," said Dr Kalon Gopinadhan of NUS Nanoscience and Nanotechnology Institute (NUSNNI) and the Centre for Advanced 2D Materials (CA2DM).
"We found that a bilayer structure of graphene and boron nitride displays an extremely large response with magnetic fields. This combination can be utilised for magnetic field sensing applications," said Kalon, who worked in the team that also included Professor Thirumalai Venkatesan, Director of NUSNNI.
Compared to other existing sensors, which are commonly made of silicon and indium antimonide, the group's hybrid sensor displayed much higher sensitivity to magnetic fields.
In particular, when measured at 127 degrees Celsius (the maximum temperature which most electronics products are operated at), the researchers observed a gain in sensitivity of more than eight-fold over previously reported laboratory results and more than 200 times that of most commercially available sensors.
Potential applications for the new sensor include the automotive industry, where sensors in cars, located in devices like flow meters, position sensors and interlocks, are currently made of silicon or indium antimonide.
The research was published in the journal Nature Communications.
