The work was reported April 16 in the online edition of Proceedings of the National Academy of Sciences.
The research focused on an inexpensive phase-change memory alloy composed of germanium, antimony and tellurium, called GST for short. The material is already used in rewritable optical media, including CD-RW and DVD-RW discs. But by using diamond-tipped tools to apply pressure to the materials, the Johns Hopkins-led team uncovered new electrical resistance characteristics that could make GST even more useful to the computer and electronics industries.
“This phase-change memory is more stable than the material used in the current flash drives. It works 100 times faster and is rewritable about 100,000 times,” said the study’s lead author, Ming Xu, a doctoral student in the Department of Materials Science and Engineering in Johns Hopkins’ Whiting School of Engineering. “Within about five years, it could also be used to replace hard drives in computers and give them more memory.”
GST is called a phase-change material because, when exposed to heat, areas of GST can change from an amorphous state, in which the atoms lack an ordered arrangement, to a crystalline state, in which the atoms are neatly lined up in a long-range order. In its amorphous state, GST is more resistant to electric current. In its crystalline state, it is less resistant. The two phases also reflect light differently, allowing the surface of a DVD to be read by A tiny laser. The two states correspond to one and zero, the language of computers.
Although this phase-change material has been used for at least two decades, the precise mechanics of this switch from one state to another have remained something of a mystery because it happens so quickly -- in nanoseconds -- when the material is heated.
To solve this mystery, Xu and his team used another method to trigger the change more gradually. The researchers used two diamond tips to compress the material. They employed a process called X-ray diffraction and a computer simulation to document what was happening to the material at the atomic level. The researchers found that they could “tune” the electrical resistivity of the material during the time between its change from amorphous to crystalline form.
“Instead of going from black to white, it’s like finding shades or a shade of gray in between,” said Xu’s doctoral adviser, En Ma, a professor of materials science and engineering, and a co-author of the PNAS paper. “By having a wide range of resistance, you can have a lot more control. If you have multiple states, you can store a lot more data.”
Other co-authors of the paper were Y. Q. Cheng of Johns Hopkins and the Oak Ridge National Laboratory in Tennessee; L. Wang of the Carnegie Institution of Washington in Argonne, Ill., and Jilin University in China; H. W. Sheng of George Mason University in Fairfax, Va.; Y. Meng and W. G. Wang of the Carnegie Institution of Washington; and X. D. Han of Beijing University of Technology in China.
Funding for the research was provided by the U.S. Department of Energy, the Office of Naval Research, the Chinese National Basic Research Program, the National Science Foundation, the W. M. Keck Foundation and Argonne National Laboratory.
Phil Sneiderman | Newswise Science News
Game-changing finding pushes 3D-printing to the molecular limit
20.06.2018 | University of Nottingham
Creating a new composite fuel for new-generation fast reactors
20.06.2018 | Lobachevsky University
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
21.06.2018 | Earth Sciences
21.06.2018 | Life Sciences
21.06.2018 | Earth Sciences