New method of producing nanomagnets for information technology

January 23, 2013, Helmholtz Association of German Research Centres
The layer system of cobalt (bottom) and organic molecules can serve to store magnetic information that is indicated in the image by ones and zeros. The green and red arrows show the orientation of the spin. Credit: Forschungszentrum Jülich

An international team of researchers has found a new method of producing molecular magnets. Their thin layer systems made of cobalt and an organic material could pave the way for more powerful storage media as well as faster and more energy-efficient processors for information processing. The results of this research have been published in the current issue of the renowned journal Nature.

In order to boost the performance of computers and reduce their , processors and have become smaller and smaller over the years. However, this strategy is about to reach the limits imposed by physics. Components that are too small are unstable, making them unsuitable for secure data storage and processing. One reason is that even one atom more or less can change the physical properties of components significantly that consist of only a few atoms. However, the exact number and arrangement of atoms can hardly be controlled in metals and semiconductors - the materials that electronic device components are made of today.

One way out of this dilemma could be so-called "", with nanometre-scale components made up of molecules. Molecules consist of a fixed number of atoms, can be designed specifically for various purposes, and can be produced cost-effectively in an identical form over and over again. If the of the electron – the "spin" – is also exploited in addition to its electric charge, it looks as though it may even be possible to implement entirely new functionalities, such as non-volatile RAM or quantum computers.

Molecules for such "molecular " must have specific . However, these properties are very sensitive and, so far, frequently become lost if the molecules are attached to , which are required for conducting electric current. This is why a team of researchers from Forschungszentrum Jülich, the University of Göttingen, Massachusetts Institute of Technology in the USA, Ruđer Bošković Institute in Croatia and IISER Kolkata in India pursued a new strategy exploiting the unavoidable interactions between the molecules and their substrate in a targeted manner to produce a hybrid layer that exhibits molecular magnetism and has the desired properties.

The researchers applied zinc methyl phenalenyl, or ZMP for short, a small metalorganic molecule which in itself is not magnetic, onto a magnetic layer of cobalt. They showed that ZMP forms a magnetic "sandwich" only in combination with the cobalt surface and that it can be selectively switched back and forth between two magnetic states using magnetic fields. In this process, the electrical resistance of the layer system changes by more than 20 %. In order to produce these "magnetoresistive" effects necessary to store, process, and measure data in molecular systems, researchers often required temperatures well below -200 °C.

"Our system is highly magnetoresistive at a comparatively high temperature of -20 °C. This is a considerable step forward on the way to developing molecular and logic elements that work at room temperature," says Jülich scientist Dr. Nicolae Atodiresei, a theoretical physicist at the Peter Grünberg Institute and the Institute for Advanced Simulation. He and his Jülich colleagues played a major role in developing a physical model that explains the properties of this material with the help of calculations on supercomputers at Forschungszentrum Jülich.

"We now know that it is necessary for the molecule to be practically flat," says Atodiresei. "Two molecules then form a stack and attach themselves closely to the cobalt surface. The cobalt and the lower molecules then form the magnetic sandwich, while the upper molecule serves as a 'spin filter' and allows primarily those electrons to pass whose spin is suitably oriented." The orientation can be controlled by means of a magnetic field, for example. On the basis of their findings, the researchers are now planning to further optimize their sandwich system and modify it in such a way that the filter effect can also be controlled by electrical fields or light pulses.

Explore further: Magnetic spin on non-magnetic materials

More information: Interface-engineered templates for molecular spin memory devices; K.V. Raman et al.; Nature 1/24/2013; DOI: 10.1038/nature11719

Related Stories

Magnetic spin on non-magnetic materials

February 14, 2012

( -- Nanotechnologists from the University of Twente's MESA+ and MIRA research institutes have developed a method for incorporating magnetic elements into non-magnetic materials in a highly controlled way. Using ...

Semiconductors with electric and magnetic properties

October 17, 2012

European scientists developed solid-state semiconductor components with magnetic properties, a prerequisite for a new generation of electronic devices exploiting both the charge and the spin of electrons.

Powerful new way to control magnetism

August 23, 2010

A team of scientists at Rutgers University has found a material in which an electric field can control the overall magnetic properties of the material. If the magnetoelectric effect discovered by the Rutgers group can be ...

Researchers switch magnetism of individual molecules

June 14, 2012

Using individual molecules instead of electronic or magnetic memory cells would revolutionise data storage technology, as molecular memories could be thousand-fold smaller. Scientists of Kiel University took a big step towards ...

Combining opposing properties for synergistic function

June 27, 2012

The properties of nanomaterials often differ in novel ways from those of the bulk material of the same substances. European researchers investigated a completely new class of such materials that could be important for magnetic ...

Recommended for you

Hauling antiprotons around in a van

February 22, 2018

A team of researchers working on the antiProton Unstable Matter Annihilation (PUMA) project near CERN's particle laboratory, according to a report in Nature, plans to capture a billion antiprotons, put them in a shipping ...

Urban heat island effects depend on a city's layout

February 22, 2018

The arrangement of a city's streets and buildings plays a crucial role in the local urban heat island effect, which causes cities to be hotter than their surroundings, researchers have found. The new finding could provide ...

New quantum memory stores information for hours

February 22, 2018

Storing information in a quantum memory system is a difficult challenge, as the data is usually quickly lost. At TU Wien, ultra-long storage times have now been achieved using tiny diamonds.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.