Researchers from the National University of Singapore (NUS) have developed a new hybrid magnetic sensor that is more sensitive than most commercially available sensors. This 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.
The invention, led by Associate Professor Yang Hyunsoo of the Department of Electrical and Computer Engineering at NUS' Faculty of Engineering, was published in the journal Nature Communications in September 2015.
High performance magnetic sensors in demand
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 the team led by Assoc Prof Yang, who is also with the NUS Nanoscience and Nanotechnology Institute (NUSNNI) and the Centre for Advanced 2D Materials (CA2DM) at NUS Faculty of Science, may finally meet these requirements. Other members of the interdisciplinary research team include Dr Kalon Gopinadhan of NUSNNI and CA2DM; Professor Thirumalai Venkatesan, Director of NUSNNI; Professor Andre K. Geim of the University of Manchester; and Professor Antonio H. Castro Neto of the NUS Department of Physics and Director of CA2DM.
More than 200 times more sensitive than commercially available sensors
The new 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.
Dr Kalon said, "We started by trying to understand how graphene responds under the magnetic field. 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."
http://www.sciencedaily.com/releases/2015/10/151030111434.htm
