(NanoRealm) - A researcher at North Carolina State University has developed a computer chip that can store an unprecedented amount of data - enough to hold an entire library's worth of information on a single chip. The new chip stems from a breakthrough in the use of nanodots, or nanoscale magnets, and represents a significant advance in computer-memory technology.

"We have created magnetic nanodots that store one bit of information on each nanodot, allowing us to store over one billion pages of information in a chip that is one square inch," says Dr. Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and author of the research.
The breakthrough is that these nanodots are made of single, defect-free crystals, creating magnetic sensors that are integrated directly into a silicon electronic chip. These nanodots, which can be made uniformly as small as six nanometers in diameter, are all precisely oriented in the same way - allowing programmers to reliably read and write data to the chips.

The chips themselves can be manufactured cost-effectively, but the next step is to develop magnetic packaging that will enable users to take advantage of the chips - using something, such as laser technology, that can effectively interact with the nanodots.

The research, which was funded by the National Science Foundation, was presented as an invited talk April 7 at the 2011 Materials Research Society Spring Meeting in San Francisco.


More information: “Self Assembly of epitaxial magnetic nanostructures”, Author: J. Narayan, North Carolina State University, Presented: April 7, 2010, 2011 MRS Spring Meeting, San Francisco.

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Source: http://www.physorg.com/news191668936.html

No More Long lines Store Checkout

(NanoRealm) - Long lines at store checkouts could be history if a new technology created in part at Rice University comes to pass.

Rice researchers, in collaboration with a team led by Gyou-jin Cho at Sunchon National University in Korea, have come up with an inexpensive, printable transmitter that can be invisibly embedded in packaging. It would allow a customer to walk a cart full of groceries or other goods past a scanner on the way to the car; the scanner would read all items in the cart at once, total them up and charge the customer's account while adjusting the store's inventory.
More advanced versions could collect all the information about the contents of a store in an instant, letting a retailer know where every package is at any time.

The technology reported in the March issue of the journal IEEE Transactions on Electron Devices is based on a carbon-nanotube-infused ink for ink-jet printers first developed in the Rice lab of James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. The ink is used to make thin-film transistors, a key element in radio-frequency identification (RFID) tags that can be printed on paper or plastic.
"We are going to a society where RFID is a key player," said Cho, a professor of printed electronics engineering at Sunchon, who expects the technology to mature in five years. Cho and his team are developing the electronics as well as the roll-to-roll printing process that, he said, will bring the cost of printing the tags down to a penny apiece and make them ubiquitous.
RFID tags are almost everywhere already. The tiny electronic transmitters are used to identify and track products and farm animals. They're in passports, library books and devices that let drivers pass through tollbooths without digging for change.
The technology behind RFID goes back to the 1940s, when Léon Theremin, inventor of the self-named electronic music instrument heard in so many '50s science fiction and horror movies, came up with a spy tool for the Soviet Union that drew power from and retransmitted radio waves.
RFID itself came into being in the 1970s and has been widely adopted by the Department of Defense and industry to track shipping containers as they make their way around the world, among many other uses.
But RFID tags to date are largely silicon-based. Paper or plastic tags printed as part of a package would cut costs dramatically. Cho expects his roll-to-roll technique, which uses a gravure process rather than ink-jet printers, to replace the bar codes now festooned on just about everything you can buy.


Cho, Tour and their teams reported in the journal a three-step process to print one-bit tags, including the antenna, electrodes and dielectric layers, on plastic foil. Cho's lab is working on 16-bit tags that would hold a more practical amount of information and be printable on paper as well.
Cho came across Tour's inks while spending a sabbatical at Rice in 2005. "Professor Tour first recommended we use single-walled carbon nanotubes for printing thin-film transistors," Cho said.
Tour's lab continues to support the project in an advisory role and occasionally hosts Cho's students. Tour said Rice owns half of the patent, still pending, upon which all of the technology is based. "Gyou-jin has carried the brunt of this, and it's his sole project," Tour said. "We are advisers and we still send him the raw materials" -- the single-walled carbon nanotubes produced at Rice.
Printable RFIDs are practical because they're passive. The tags power up when hit by radio waves at the right frequency and return the information they contain. "If there's no power source, there's no lifetime limit. When they receive the RF signal, they emit," Tour said.

There are several hurdles to commercialization. First, the device must be reduced to the size of a bar code, about a third the size of the one reported in the paper, Tour said. Second, its range must increase.
"Right now, the emitter has to be pretty close to the tags, but it's getting farther all the time," he said. "The practical distance to have it ring up all the items in your shopping cart is a meter. But the ultimate would be to signal and get immediate response back from every item in your store - what's on the shelves, their dates, everything.
"At 300 meters, you're set - you have real-time information on every item in a warehouse. If something falls behind a shelf, you know about it. If a product is about to expire, you know to move it to the front - or to the bargain bin."
Tour allayed concerns about the fate of nanotubes in packaging. "The amount of nanotubes in an RFID tag is probably less than a picogram. That means you can produce one trillion of them from a gram of nanotubes - a miniscule amount. Our HiPco reactor produces a gram of nanotubes an hour, and that would be enough to handle every item in every Walmart.
"In fact, more nanotubes occur naturally in the environment, so it's not even fair to say the risk is minimal. It's infinitesimal."

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More information: Read the paper at: http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5406115
Source: RICE University - http://www.rice.edu/
From PhysOrg.com (http://www.physorg.com/news188129794.html)

(NanoRealm) - A team led by University of Wisconsin-Madison researchers has developed a new approach for creating powerful nanodevices, and their discoveries could pave the way for other researchers to begin more widespread development of these devices.

The discoveries were published in the online edition of Nature Materials (Feb. 28). Chang-Beom Eom, a UW-Madison professor of materials science and engineering, leads the team, which includes UW-Madison graduate students and research associates and collaborators from Penn State University, the University of Michigan and the University of California, Berkeley.

Particular metal-oxide materials (including some ferrites) have a unique magneto-electric property that allows the material to switch its magnetic field when its polarization is switched by an electric field and vice versa. This property means these materials can be used as bases for devices that act like signal translators capable of producing electrical, magnetic or even optical responses, and the devices can store information in any of these forms.

This could produce a variety of magnetoelectric devices with a wide range of applications, such as new integrated circuits or tiny electronic devices with the information storage capacity of hard drives.

"We all have electric and magnetic devices that run independently, but sometimes we want these functions integrated into one device with one signal used for multiple responses," says Eom.
Essentially, Eom and his team have developed a road map to help researchers "couple" a material's electric and magnetic mechanisms. As researchers run a current through a magnetoelectric device, electric signals follow the electric field like a path. The signals' ultimate destination could be, as an example, a memory "bank" operated by a magnetic field. When the researchers switch the electric field, the signals encounter a fork in the path. Though both prongs of the fork head in a similar direction, one path is the correct one and will prompt the magnetic field to switch. This will allow the information carried by the signals to be stored in the bank. If the signals take the incorrect path, the magnetic state won't switch, the bank remains inaccessible, and the information is lost as soon as the electric field turns off.

In addition to determining the proper path for the electric signals, the team has developed a matrix that ensures the cross-coupling effect is stable, or non-volatile, which allows for long-term data storage. This matrix is then embedded in thin films.

These two discoveries — the correct path and the stabilizing matrix — will allow other researchers to study the fundamental physics of cross-coupling in materials and begin investigating how to turn the many possibilities of multifunctional devices into reality.

"People have been imagining multiple uses for cross-coupling," says Eom. "This work will allow us to make nonvolatile magnetoelectric devices at the nanoscale, meaning we can store the information even after the power is turned off."

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More information: Journal: http://www.nature.com/nmat/index.html
Provided by University of Wisconsin-Madison (http://www.wisc.edu/)

Source from: http://www.physorg.com/news186670513.html

(NanoRealm) - Graphene, a one-atom-thick layer of a carbon lattice with a honeycomb structure, has great potential for use in radios, computers, phones and other electronic devices. But applications have been stymied because the semi-metallic graphene, which has a zero band gap, does not function effectively as a semiconductor to amplify or switch electronic signals.
 While cutting graphene sheets into nanoscale ribbons can open up a larger band gap and improve function, 'nanoribbon' devices often have limited driving currents, and practical devices would require the production of dense arrays of ordered nanoribbons — a process that so far has not been achieved or clearly conceptualized.

But Yu Huang, a professor of materials science and engineering at the UCLA Henry Samueli School of Engineering and Applied Science, and her research team, in collaboration with UCLA chemistry professor Xiangfeng Duan, may have found a new solution to the challenges of graphene.

In research to be published in the March issue of Nature Nanotechnology (currently available online), Huang's team reveals the creation of a new graphene nanostructure called graphene nanomesh, or GNM. The new structure is able to open up a band gap in a large sheet of graphene to create a highly uniform, continuous semiconducting thin film that may be processed using standard planar semiconductor processing methods.

"The nanomeshes are prepared by punching a high-density array of nanoscale holes into a single or a few layers of graphene using a self-assembled block copolymer thin film as the mask template," said Huang.

The nanomesh can have variable periodicities, defined as the distance between the centers of two neighboring nanoholes. Neck widths, the shortest distance between the edges of two neighboring holes, can be as low as 5 nanometers.

This ability to control nanomesh periodicity and neck width is very important for controlling electronic properties because charge transport properties are highly dependent on the width and the number of critical current pathways.

Using such nanomesh as the semiconducting channel, Huang and her team have demonstrated room-temperature transistors that can support currents nearly 100 times greater than individual graphene nanoribbon devices, but with a comparable on-off ratio. The on-off ratio is the ratio between the currents when a device is switched on or switched off. This usually reveals how effectively a transistor can be switched off and on.

The researchers have also shown that the on-off ratio can be tuned by varying the neck width.

"GNMs can address many of the critical challenges facing graphene, as well as bypass the most challenging assembly problems," Huang said. "In conjunction with recent advances in the growth of graphene over a large-area substrate, this concept has the potential to enable a uniform, continuous semiconducting nanomesh thin film that can be used to fabricate integrated devices and circuits with desired device size and driving current.

"The concept of the GNM therefore points to a clear pathway towards practical application of graphene as a semiconductor material for future electronics. The unique structural and electronic characteristics of the GNMs may also open up exciting opportunities in highly sensitive biosensors and a new generation of spintronics, from magnetic sensing to storage," she said.

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Source: PhysOrg.com: http://www.physorg.com/news186397884.html
Provided by University of California - Los Angeles: http://www.ucla.edu/
Nature Nanotechnology Paper Abstract: http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2010.8.html

(NanoRealm) - Telecommunications researchers in Japan are attempting to create electronic sensors that can not only receive information from the brain, but could manipulate our neural pathways.

While the concept might conjure science-fiction images of half-human, half-machine cyborgs, Dr Keiichi Torimitsu of Nippon Telegraph and Telephone (NTT), says the research is more likely to provide relief for people with Parkinson's disease or overcoming stroke.

Torimitsu presented his team's work on the development of bionic, or bio-mimetic, brain sensors at this week's International Conference on Nanoscience and Nanotechnology (ICONN) in Sydney.

"Establishing connections between the brain and electrical instruments is important for understanding how the brain works and for controlling neural activity," says Torimitsu, who heads NTT's Molecular and Bioscience Group.

"To develop some kind of devices or interfaces with the brain that would make it possible to transmit our information, sending it through the telecommunication pathways to another person or device such as a computer - that is the goal."

A neural interface would be a significant achievement in the rapidly advancing realm of bionic technology, which includes devices such as the cochlear ear implant.

Nano-connections

Torimitsu is working on creating a nano-scaled implant comprising a nano-electrode coated with an artificial membrane that mimics the receptor proteins found on the surface of brain cells, such as glutamate and GABA receptors -involved in increasing and inhibiting brain activity.

Interactions between the receptors and neurotransmitters naturally generate electrical activity. Carefully placed nano-electrodes receive the neurotransmissions providing an instant, accurate electrical reflection of what is occurring, which can be read by an external device.

Torimitsu hopes it would not only monitor activity, but also interact in the connections between neurons known as the synapses.

Ideally, he says, the device would use a biological energy source such as glucose.

"If we could use those proteins on a nano-electrode to generate electrical responses, we could achieve the bio-mimicry of responses."

Torimitsu admits there are a number of hurdles to overcome such as adverse immune responses and possible faults with the machinery. He says at this stage it's unlikely that healthy people would volunteer to have the devices implanted.

But, Torimitsu says it has great medical potential for stroke sufferers and people with Parkinson's disease where brain activity could be controlled.

Australian connections

The Japanese team is working with several researchers in Australia to refine the concept and devise applications for the technology.

Torimitsu has been working with Dr Simon Koblar of the University of Adelaide's Centre for Molecular Genetics of Development, looking at how to apply the technology for the treatment of stroke sufferers.

He is also about to commence working with the University of Wollongong's Intelligent Polymer Research Institute, which works at the forefront of bionics.

Director of the Institute, Professor Gordon Wallace, says one of the goals is to improve the interface with cochlear implant.

He says Torimitsu's work - a meeting of telecommunications technology and biological knowledge - shows why it makes it a very exciting time to be doing such research.

"People are starting to realise all around the world that there are lots of tools that we can use that we already have at our disposal to make this field progress very quickly," says Wallace.

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Source: ABC News (http://www.abc.net.au/science/articles/2010/02/25/2830261.htm)