System Bits: Oct. 10

Skyrmions for data storage: vibration-driven logic gate; Wii helps Parkinson’s patients.


Fast-moving magnetic particles for data storage
According to MIT researchers, an exotic kind of magnetic behavior discovered just a few years ago holds great promise as a way of storing data — one that could overcome fundamental limits that might otherwise be signaling the end of Moore’s Law.

Rather than reading and writing data one bit at a time by changing the orientation of magnetized particles on a surface, as today’s magnetic disks do, the MIT team said the new system would make use of tiny disturbances in magnetic orientation, called “skyrmions.”

These virtual particles, which occur on a thin metallic film sandwiched against a film of different metal, can be manipulated and controlled using electric fields, and can store data for long periods without the need for further energy input.

“One of the biggest missing pieces needed to make skyrmions a practical data-storage medium was a reliable way to create them when and where they were needed, so this is a significant breakthrough.” — MIT associate professor of materials science and engineering, Geoffrey Beach.

(Source: MIT)

Last year, a team led by MIT associate professor of materials science and engineering Geoffrey Beach documented the existence of skyrmions, but the particles’ locations on a surface were entirely random. Now, Beach has collaborated with others to demonstrate experimentally for the first time that they can create these particles at will in specific locations, which is the next key requirement for using them in a data storage system. An efficient system for reading that data will also be needed to create a system that could be commercialized.

The team included researchers at the Max Born Institute and the Institute of Optics and Atomic Physics, both in Berlin; the Institute for Laser Technologies in Medicine and Metrology at the University of Ulm, in Germany; and the Deutches Elektroniken-Syncrotron (DESY), in Hamburg.

Vibration-driven logic gate
According to researchers at King Abdullah University of Science and Technology (KAUST), vibrating mechanical switches that can be cascaded to perform complex computational operations could take computing significantly further than today’s technologies. The team has demonstrated an alternative technology based on mechanical vibrations.

They reminded that the microcomputer processors found inside every computer, mobile phone and microwave comprise mind-bogglingly complex networks of millions or billions of microscopic transistors—electrical switches turn on when a current flows across their terminals. These transistors are networked together to construct logic gates that perform operations, such as AND (when two inputs are on) and OR (when either input is on). In turn, these logic gates are connected to much larger networks to allow increasingly complex operations. However, with each transistor consuming electrical current and generating heat even when not being actively switched, and with transistors approaching their physical limits of miniaturization and efficiency, the search is on for alternative technology that will eventually replace the electrical transistor and take computing into the future.

The cascadable, vibration-driven microelectromechanical logic gate takes electrical signals as inputs and produces a logic output (1 or 0) based on the resonance of the microbeam.
(Source: KAUST)

Doctoral researchers, Saad Ilyas and Nizar Jaber, in the laboratory of Mohammad Younis, have demonstrated what they say is a scalable, efficient alternative technology, not based on electrical current, but on mechanical vibrations excited by multifrequency electrical inputs.

“Electromechanical systems offer a major advantage over existing technology in that they are leakage free: that is, unlike electrical transistors, they only consume power when switched,” Ilyas said. “They also require fewer gates per computing function, resulting in lower complexity, and they can be fabricated with higher integration densities—it is even predicted that these systems could be scaled down to the molecular level.”

Microelectromechanical systems (MEMS) have been investigated in the past for logic operations, but it has been a challenge to devise a mode of operation that allows the MEMS logic gates to be cascaded to form arbitrary computational functions. Jaber and Younis have come up with a novel technique to perform logic operations using MEMS based on frequency mixing, which holds great potential for cascading.
They use an electrical signal as an input, which causes a clamped polymer microbeam to vibrate at a certain resonance frequency. This in turn generates motional current as an electrical signal with the same frequency, which could then be cascaded into the input of another MEMS logic gate.

The team has shown various logic operations at a single operating frequency, which is an important step towards cascading as the next milestone in MEMS resonator-based computing. The assert that their logic gates are also compatible with existing fabrication techniques.

Wii games help Parkinson’s patients
Professors Jessica Huber and Jeff Haddad from the College of Health and Human Sciences at Purdue University are using the Nintendo Wii gaming system to help people with Parkinson’s disease; studying how playing specially created games can improve a patient’s movement, speech and overall quality of life.

By having study participants stand on a balance board and move a cursor to a specific target on a monitor, the researchers said they are studying how brain activity and body movement are connected, which often comes into play in seemingly simple everyday tasks like walking and talking, which can be difficult for people with Parkinson’s.

Interestingly, a pilot study done in collaboration with researchers at Purdue, Indiana University and the University of Calgary, using Parkinson’s patients along with otherwise healthy older adults, revealed that the games, when utilized for a prescribed period of time, tended to show more positive outcomes in gait and balance than traditional Parkinson’s treatments.

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