Over the last decade, advances in the field of flexible electronics have reinvigorated the global electronics industry. The new features such as flexibility, conformability and disposability etc. of this new generation electronics have been made possible with fabrication of electronics directly on non-conventional substrates such as paper and plastic etc. The possibility of having electronics on paper and plastic also opens opportunities for innovative use of electronics in challenging areas such as counterfeit currency.
Magnetic transducers are widely used in modern industry and electronics to sense the magnetic field strength to measure current, position, motion, direction, and other physical parameters. Recent progresses of Giant Magnetic Resistance (GMR) has opened a new opportunity as it allows controlling an electronic device in non-contact mode by means of localized magnetic fields. The GMR sensors are particularly interesting as the resistance of their ferromagnetic layers can be altered by external magnetic field, which can be used to trigger the electronic circuits. The integration of GMR components onto a flexible device requires overcoming several practical challenges. These include relatively lower GMR response compared to rigid counterparts, performance instability due to elastic mismatch when deformed, induced strain effects due to substrate roughness, and higher anisotropy and switching fields of magnetic free layer causing interference with other coupled components etc.
This proposed project will realize GMR sensor on paper surpassing these difficulties and provide a breakthrough towards novel applications such as preventing currency counterfeits. The magnetic sensing devices developed by the proposed approach also could advance in the area of magnetic sensors for flexible electronics and soft robotics which is challenging with conventional approaches. The research also can also provide more scientific understanding on the fundamentals of magnetic materials and devices.
The major goals of the project are
(1) synthesize and characterize controlled composition of nanoparticles for example FeCo and Cu
(2) develop GMR by printing multiple alternate layers of the nanoparticles on paper
(3) integrate the paper-GMR sensor with other electronic components on flexible substrates and
(4) demonstrating the efficacy of proposed system in different applications including the detection of counterfeit currency.
