Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New Speed Record for Magnetic Memories

Ballistic spin torque switching enables ultra fast non-volatile memories

An experiment carried out at the Physikalisch-Technische Bundesanstalt (PTB) has realized spin torque switching of a nanomagnet as fast as the fundamental speed limit allows. Using this so-called ballistic switching future non-volatile magnetic memories could operate as fast as the fastest non-volatile memories. The experiments are described in the next issue of Physical Review Letters (22 August, 2008.

Fast memory chips such as DRAMs and SRAMs (Dynamic and Static Random Access Memory) commonly used today have one decisive disadvantage: in case of power interruption, they lose their stored information. This problem could be solved by magnetic memory chips called MRAMs (Magnetic Random Access Memory). In MRAM the digital information is not stored by means of electric charge but by means of the orientation of the magnetization of a magnetic cell.

The latest generation of MRAM uses the so-called spin torque effect for programming the magnetic bits. Using spin torque the memory state of the cell can be programmed in a very simple way just by applying a current pulse. A positive current switches the magnetization to one direction (digital state "0") and a negative current to the other (digital state "1"). Spin torque MRAM further promise a high storage density comparable to DRAM and Flash. Most major semiconductor chip producers are developing spin torque memories and market introduction is expected, soon.

A spin torque current pulse excites a rotational motion of the magnetization of the memory cell - the so-called precession. Normally, the magnetization has to undergo several precessional turns before reliable magnetization reversal takes place. Therefore present spin torque MRAM prototypes must operate with rather long write pulses of about 10 nanoseconds duration which limits the MRAM clock speed.

In the experiment carried out at PTB Braunschweig spin torque magnetization reversal has now been realized by a single precessional turn, only. This so called "ballistic" spin torque magnetization reversal corresponds to the ultra short physical limit of spin torque magnetization reversal time. It was achieved by precise tailoring of the current pulse parameters in combination with a small magnetic bias field.

Using ballistic spin torque reversal future MRAM could be programmed by current pulses shorter than 1 nanosecond corresponding to write clock rates well above 1 GHz. It could thus enable a high-density and non-volatile memory operating at the clock rates of the fastest volatile memories.

Original publication:
Quasi-ballistic spin torque magnetization reversal S. Serrano-Guisan, K. Rott, G. Reiss, J. Langer, B. Ocker, and H. W. Schumacher Physical Review Letters 33 (2008)
Dr. Hans Werner Schumacher, PTB Working Group 2.53 Low-dimensional Electron Systems,

Phone: +49531-592-2414, e-mail:

Dr. Hans Werner Schumacher | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR

nachricht Taming chaos: Calculating probability in complex systems
21.03.2018 | American Institute of Physics

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Modular safety concept increases flexibility in plant conversion

22.03.2018 | Trade Fair News

New interactive map shows climate change everywhere in world

22.03.2018 | Earth Sciences

New technologies and computing power to help strengthen population data

22.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>