Organic spintronics - Page 3

Commonly used industrial dyes hold the key to advancing the new science of 'spintronics', say researchers working on a new a £2.5 million study.

The new Basic Technology grant awarded by the Engineering and Physical Sciences Research Council will support research into the magnetic properties of metal atoms found in industrial dyes such as Metal Phthalocyanine (MPc), a blue dye used in clothing. The team from the London Centre for Nanotechnology - a joint venture between Imperial College London and University College London - and the University of Warwick believes that finding ways to control and exploit these molecules will allow spintronics to be applied in new ways.

In order to advance spintronics, materials which combine both magnetic and semiconducting properties need to be found. The researchers believe that MPc, which is an organic semiconductor, holds the answer, and now aim to exploit the spin inherent in its metal atoms. Previous research carried out by this team has already demonstrated that spins in MPc can interact and these interactions can be switched – such switching is the first step towards use in information storage and logic operations.

The organic semiconductors to be used by the team for spintronics are very similar to those successfully used in solar cells and OLEDs, and which are leading the way into cheap 'plastic electronics'. This means that the benefits of organic semiconductors will be spread to more components of everyday electronics products such as computers and mobile telephones.

The research team of electrical and computer engineers from the Virginia Commonwealth University’s School of Engineering and the University of Cincinnati examined the ‘spin’ of electrons in organic nanowires, which are ultra-small structures made from organic materials. These structures have a diameter of 50 nanometers, which is 2,000 times smaller than the width of a human hair. The spin of an electron is a property that makes the electron act like a tiny magnet. This property can be used to encode information in electronic circuits, computers, and virtually every other electronic gadget.

"In order to store and process information, the spin of an electron must be relatively robust. The most important property that determines the robustness of spin is the so-called 'spin relaxation time,' which is the time it takes for the spin to 'relax.' When spin relaxes, the information encoded in it is lost. Therefore, we want the spin relaxation time to be as long as possible," said corresponding author Supriyo Bandyopadhyay, Ph.D., a professor in the Department of Electrical and Computer Engineering at the VCU School of Engineering.
"Typically, the spin relaxation time in most materials is a few nanoseconds to a few microseconds. We are the first to study spin relaxation time in organic nanostructures and found that it can be as long as a second. This is at least 1000 times longer than what has been reported in any other system," Bandyopadhyay said.

The team fabricated their nanostructures from organic molecules that typically contain carbon and hydrogen atoms. In these materials, spin tends to remain relatively isolated from perturbations that cause it to relax. That makes the spin relaxation time very long.

Read more here (NanoWerk)

Researchers at the National Institute of Standards and Technology have made the first confirmed “spintronic” device incorporating organic molecules, a potentially superior approach for innovative electronics that rely on the spin, and associated magnetic orientation, of electrons. The physicists created a nanoscale test structure to obtain clear evidence of the presence and action of specific molecules and magnetic switching behavior.

Spintronic devices usually are made of inorganic materials. The use of organic molecules may be preferable, because electron spins can be preserved for longer time periods and distances, and because these molecules can be easily manipulated and self-assembled. However, until now, there has been no experimental confirmation of the presence of molecules in a spintronic structure. The new NIST results are expected to assist in the development of practical molecular spintronic devices.