Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnets see the light

18.02.2002


Light-tunable magnets would work only in the coolest computers.
© Getty Images


Light-sensitive ’plastic’ magnets could replace your hard drive.

A ’plastic’ magnet that responds to light could lead to new ways of storing and reading large amounts of computer data. Light would be used to store information in cheap, fast and high-capacity ’magneto-optic’ memories.

The light-switchable magnet is the first to be made from organic (carbon-based) molecules. This means its discoverers, Arthur Epstein of Ohio State University in Columbus and Joel Miller of the University of Utah in Salt Lake City, should be able to use clever chemical tricks to fine-tune the properties of the material1.



Their first goal is to raise the temperature at which the magnetic switching operates. At present, the material works only when cooled to below -198 oC.

Although this sounds impractically low, it is within spitting distance of the temperature at which nitrogen liquefies:
-196 oC. A relatively cheap refrigerant, liquid nitrogen could quite feasibly be used to cool commercial devices incorporating a modified light-sensitive magnet, Epstein and colleagues hope.

Magnetic memories store information in tiny ’magnetized domains’, where magnetic field lines points either ’up’ or ’down’. This allows magnetic media to store the binary (zeros and ones) data of the digital world. In conventional magnetic memories, the direction of the magnetic field is switched electronically; magneto-optic systems do the switching with light, usually from lasers.

There is nothing new about magneto-optic memories. Some commercial hard-disk drives already exist that use light to read and write information stored in magnetic films. But in these systems the laser switches the magnetic medium by warming it.

Epstein and colleagues’ material contains manganese atoms mixed with small organic molecules, and becomes more magnetic when it absorbs blue light. The light alters the shape of the organic molecules, changing their magnetic properties. The researchers can reverse the effect either by shining green light on the material or by heating it above
-23oC.

In a future memory device, information could be encoded in the material as regions of ’stronger’ or ’weaker’ magnetism, which could be written and erased using tightly focused lasers. This could lead to information storage at very high densities.

Epstein admits that applications of this effect are still a long way off - the organic magnet needs a lot of improvement before it has the properties demanded of commercial devices.

References

  1. Pejakovic, D. A., Kitamura, C., Miller, J. S. & Epstein, A. J. Photoinduced magnetization in the organic-based magnet Mn(TCNE)x.y(CH2Cl2). Physical Review Letters, 88, 057202, (2002).

PHILIP BALL | © Nature News Service

More articles from Information Technology:

nachricht Open source software helps researchers extract key insights from huge sensor datasets
22.03.2019 | Universität des Saarlandes

nachricht Touchscreens go 3D with buttons that pulsate and vibrate under your fingertips
14.03.2019 | Universität des Saarlandes

All articles from Information Technology >>>

The most recent press releases about innovation >>>

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

Im Focus: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Solving the efficiency of Gram-negative bacteria

22.03.2019 | Life Sciences

Bacteria bide their time when antibiotics attack

22.03.2019 | Life Sciences

Open source software helps researchers extract key insights from huge sensor datasets

22.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>