Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Resetting the future of MRAM

07.03.2012
Helmholtz-Zentrum Berlin developed a magnetic valve that novel electronic devices can be realistic

In close collaboration with colleagues from Bochum and the Netherlands, researchers from the Helmholtz-Zentrum Berlin (HZB) have developed a novel, extremely-thin structure made of various magnetic materials.


A pictorial view of the coupling mechanism between hard and soft ferrimagnetic alloys with perpendicular magnetization. Picture: RUB/Abrudan

It is suitable as a kind of magnetic valve for data-storage units of the most recent generation and makes use of effects in the context of so-called spintronics, with which, in addition to the (re-)charging process, magnetic characteristics of the electrons can also be used for information-processing and -storage. The advantage of the new structure: data remain intact even after the electric current has been switched off and the memory can be re-written more or less indefinitely.

The scientists published their results in the technical magazine Nature Communications (DOI: 10.1038/ncomms1728).

Everything began with basic academic curiosity; “First of all we just wanted to create a defined anisotropy with two thin, stacked ferrimagnetic layers”, says Florin Radu, physicist at the Institute for Complex Magnetic Materials of the Helmholtz-Zentrum Berlin (HZB) and principal author of the research paper. In other words, the researchers just wanted to create a structure in which a magnetic characteristic within the material changes in a well defined way. Experts in this field define this as magnetic hysteresis. It describes the behaviour of magnetic substances vis-à-vis an externally-applied magnetic field. However, the task proved to be much more difficult; the magnetic energies at the interfaces turned out to be so powerful that the magnetization of the films reverses together. It was necessary to place an additional, non-magnetic layer made of tantalum between the ferrimagnetic layers in order to diminish this effect.

What the scientists saw next was truly astounding; the system behaved fundamentally differently as compared to the conventional systems made of ferromagnetic and anti-ferromagnetic layers. The ferrimagnet described as magnetically “soft”, which consists of the chemical elements iron and gadolinium, unexpectedly indicated an alteration in the hysteresis, while the existing magnetism remained unaltered for the “hard” ferrimagnetic film that consists of the chemical elements dysprosium and cobalt.

This discovery paves the way for an even more vigorous research in the field of spintronics. “Know how, Show how!”, thus proclaims the research maxim of Radu. “I would not be surprised to see this discovery implemented into PC’s, smart phones and tablets in the future”, he predicts. For his invention the so-called spin-valve the HZB filed a patent application this week.

Nowadays, the data storage units are either volatile or non-volatile. For the former, the information is lost as soon as the device is switched off, and for the latter the information remain intact for many years. Due to thermal effects, they are also practically unusable after about ten years. In particular, when the bits are only a few nanometres in size, they lose stability. Once lost, the magnetization direction of the hard magnetic layer cannot easily be set again in the original direction. This leads to irretrievably loss of data.

This stability issue can now be addressed with the new spin-valve concept. By tunning the magnetic properties of the hard ferrimagnetic layer, the so-called RAM memory building-blocks (RAM stands for random access memory) can be manufactured with controlled life-time of the stored information of weeks, months or years. Thereafter, the magnetic orientation can be reset in the original state, which increases considerably the overall life expectancy of the information as compared to the existing non-volatile MRAM (Magnetoresistive Random Access Memory). These memory building-blocks are now certainly highly sought-after in the field of micro-electronics, but have not been able, to date, to be established in the markets due to high costs and technical problems.

With the spin-valve concept by Radu and his colleagues, electronic devices can now be developed that, similar to the MRAM technology, are operable immediately after being switched on and allow their data storage units to be re-written more or less indefinitely.

Scientific original publication:
F. Radu, R. Abrudan, I. Radu, D. Schmitz, H. Zabel: Perpendicular exchange bias in ferrimagnetic spin valves. Nature Communications, 2012. DOI: 10.1038/ncomms1728

Dr. Florin Radu | EurekAlert!
Further information:
http://www.helmholtz-berlin.de

More articles from Physics and Astronomy:

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

nachricht A quantum entanglement between two physically separated ultra-cold atomic clouds
17.05.2018 | University of the Basque Country

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: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>