Plastic flexible magnetic memory device

It looks like a small piece of transparent film with tiny engravings on it and is flexible enough to be bent into a tube. Yet, this piece of smart plastic demonstrates excellent data storage and processing performance. This invention, developed by researchers from the National University of Singapore (NUS), brings researchers a step closer toward making flexible, wearable electronics a reality.

The technological advancement is achieved in collaboration with researchers from Yonsei University, Ghent University, and Singapore’s Institute of Materials Research and Engineering. The research team has successfully embedded a powerful magnetic memory chip on a flexible plastic material, and this malleable memory chip will be a critical component for the design and development of flexible and lightweight devices. Such devices have great potential in applications such as automotive, healthcare electronics, industrial motor control and robotics, industrial power and energy management, as well as military and avionics systems.

Enabler for flexible electronics

Flexible magnetic memory devices have attracted a lot of attention as they are the fundamental component required for data storage and processing in wearable electronics and biomedical devices, which require functions such as wireless communication, information storage, and code processing. Although a substantial amount of research has been conducted on different types of memory chips and materials, challenges still exist in fabricating high performance memory chips on soft substrates that are flexible, without sacrificing performance.

To address the current technological challenges, the research team, led by Associate Prof. Yang Hyunsoo of the Department of Electrical and Computer Engineering at the NUS Faculty of Engineering, developed the technique that implants a high-performance magnetic memory chip on a flexible plastic surface.

Operating on magnetoresistive random access memory (MRAM), the device uses a magnesium oxide (MgO)-based magnetic tunnel junction (MTJ) to store data. MRAM outperforms conventional random access memory (RAM) computer chips in many aspects, including the ability to retain data after a power supply is cut off, high processing speed, and low power consumption.

The research team first grew the MgO-based MTJ on a silicon surface, and then etched away the underlying silicon. Using a transfer printing approach, the team implanted the magnetic memory chip on a flexible plastic surface made of polyethylene terephthalate while controlling the amount of strain caused by placing the memory chip on the plastic surface.

“Our experiments showed that our device’s tunneling magnetoresistance could reach up to 300% – it’s like a car having extraordinary levels of horsepower. We have also managed to achieve improved abruptness of switching. With all these enhanced features, the flexible magnetic chip is able to transfer data faster,” Hyunsoo says. “Flexible electronics will become the norm in the near future, and all new electronic components should be compatible with flexible electronics. We are the first team to fabricate magnetic memory on a flexible surface, and this significant milestone gives us the impetus to further enhance the performance of flexible memory devices and contribute towards the flexible electronics revolution.”

National University of Singapore

www.nus.edu.sg