Tag Archives: spintronics

3D microchip: “… we can actually see the data climbing this nano-staircase step by step”

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A Jan. 30, 2013 news release about a 3D microchip developed from a spintronic chip is available on EurekAlert here or at the University of Cambridge here and provides background about why a 3D microchip would be developed,

Scientists from the University of Cambridge have created, for the first time, a new type of microchip which allows information to travel in three dimensions. Currently, microchips can only pass digital information in a very limited way – from either left to right or front to back. …

Dr Reinoud Lavrijsen, an author on the paper from the University of Cambridge, said: “Today’s chips are like bungalows – everything happens on the same floor. We’ve created the stairways allowing information to pass between floors.”

Here are some of the technical details,

For the research, the Cambridge scientists used a special type of microchip called a spintronic chip which exploits the electron’s tiny magnetic moment or ‘spin’ (unlike the majority of today’s chips which use charge-based electronic technology). Spintronic chips are increasingly being used in computers, and it is widely believed that within the next few years they will become the standard memory chip.

To create the microchip, the researchers used an experimental technique called ‘sputtering’. They effectively made a club-sandwich on a silicon chip of cobalt, platinum and ruthenium atoms. The cobalt and platinum atoms store the digital information in a similar way to how a hard disk drive stores data. The ruthenium atoms act as messengers, communicating that information between neighbouring layers of cobalt and platinum. Each of the layers is only a few atoms thick.

They then used a laser technique called MOKE to probe the data content of the different layers. As they switched a magnetic field on and off they saw in the MOKE signal the data climbing layer by layer from the bottom of the chip to the top. They then confirmed the results using a different measurement method.

Here’s the source for the quote used in the headline,

Professor Russell Cowburn, lead researcher of the study from the Cavendish Laboratory, the University of Cambridge’s Department of Physics, said: “Each step on our spintronic staircase is only a few atoms high. I find it amazing that by using nanotechnology not only can we build structures with such precision in the lab but also using advanced laser instruments we can actually see the data climbing this nano-staircase step by step.

An artistic representation of the microchip and the data,

3D microchip, courtesy of the University of Cambridge. Credit LindenArtWork www.lindenartwork.com.

3D microchip, courtesy of the University of Cambridge. Credit LindenArtWork www.lindenartwork.com

Here’s a citation and a link to the paper,

Magnetic ratchet for three-dimensional spintronic memory and logic by Reinoud Lavrijsen, Ji-Hyun Lee, Amalio Fernández-Pacheco,Dorothée C. M. C. Petit, Rhodri Mansell, & Russell P. Cowburn.  Nature, 493, 647–650 (31 January 2013) doi:10.1038/nature11733 (Published online 30 January 2013)

The paper is behind a paywall.

University of British Columbia scientists put a new spin on spintronics and Scientists protest the Canadian federal budget

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Researchers at the University of British Columbia (UBC) have found a way to control an electron’s spin naturally, that is, without the use of external fields. They control the spin by bouncing the electron through a microscopic channel. Joshua Folk, Canada Research Chair in the Physics of Nanostructures and principal investigators, says (from the article at Physorg.com):

“We show that the spin of electrons can be controlled without external fields, simply by designing the right circuit geometry and letting electrons move freely through it.”

The new technique uses the natural interactions of the electrons within the semiconductor micro-channel to control their spin–a technique that is a major step, but not yet flexible enough for industrial applications, notes Folk, an Assistant Professor with Physics and Astronomy who came to UBC via the Massachusetts Institute of Technology.

It looks promising and, if successful, could lead to exponentially faster processing. Go here for more details.

I’ve been waiting for a protest and it’s finally here. Researchers have written a letter, Don’t Leave Canada Behind, protesting the 2009 federal budget cuts to science announced in January. More that 2000 signed the letter which was written on March 16, 2009. From the letter, which (as you might expect) makes reference to the stark contrast between the current Canadian and the US budgets,

“When U.S. researchers are being actively approached for ideas to use the stimulus money to think big and to hire and retain their researchers, their Canadian counterparts are now scrambling to identify budget cuts for their labs, while worrying about the future of their graduating students,”  …

There’s more here. The federal Minister for Science and Technology, Gary Goodyear, created a kerfuffle earlier this year after the budget was announced, when it seemed that he didn’t understand the concept of evolution all that well. I mention it because Goodyear is quoted, in response to this letter, as saying that the government is “… committed to innovation and discovery.” Two things, I’d like to know more about Goodyear’s understanding of science and how he expects to influence the kinds of discoveries and innovations that are made and I’m glad they are committed but I’m not sure how that will work if there aren’t enough funds to support innovation and discovery.

Happy 2009!

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I just read ‘How spintronics went from the lab to the iPod’ by W. Patrick McCray in the online January 2009 issue of Nature Nanotechnology, it’s here. The author is in the history department of the University of California at Santa Barbara and he provides an intriguing view of how nanotechnology, electronics, academic, military, and business interests converged in various applications, the best known being the iPod. He also provides a brief history of how the discovery (giant magnetoresistance) was made by two teams independently of each other (but almost simultaneously) who agreed to share credit and ultimately a Nobel prize. (BTW, that last bit contrasts nicely with Crick and Watson with their double helix and the way they took full credit when at least some should have gone to Rosalind Franklin.)

For anyone who doesn’t know about giant magnetoresistance (GMR), we start with magnetoresistance (from the article),

Magnetoresistance, a change in the electrical resistance of a conductor caused by an applied magnetic field was first observed … in 1857 (p. 2)

The source was not discovered until quantum mechanics became an area of interest,

… the physics underlying electron spin — which is the ultimate source of magnetism in most materials — dates back to … the golden era of quantum mechanics. The effect was quite small … but that all changed … in 1988. [One team in Germany and another team in France sandwiched very thin layers {1 nm} of nonmagnetic materials with magnetic materials to observe a significant {10% for one team and 50% for the other team} change in electrical resistance in the presence of a magnetic field. Presumably lowering the resistance which {researchers at IBM realized} meant that disc drives could become smaller and hold more information {which is how we ultimately with an iPod}.

GMR also represented the first example of a new kind of technology called ‘spintronics’, so-called because it exploits the spin of the electron, as well as its electric charge, store and process information. p. 2 (the stuff in square brackets is my attempt to massage the information so I don’t quote the entire article]

Do read the story.