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New discovery could pave the way for spin- based computing 25 September 2014 Electricity and magnetism rule our digital world. Semiconductors process electrical information, while magnetic materials enable long-term data storage. A University of Pittsburgh research team has discovered a way to fuse these two distinct properties in a single material, paving the way for new ultrahigh density storage and computing architectures. While phones and laptops rely on electricity to process and tempor
    New discovery could pave the way for spin-based computing 25 September 2014Electricity and magnetism rule our digital world.Semiconductors process electrical information,while magnetic materials enable long-term datastorage. A University of Pittsburgh research teamhas discovered a way to fuse these two distinctproperties in a single material, paving the way fornew ultrahigh density storage and computingarchitectures. While phones and laptops rely on electricity toprocess and temporarily store information, long-term data storage is still largely achieved viamagnetism. Discs coated with magnetic materialare locally oriented (e.g. North or South torepresent 1 and 0 ), and each independentmagnet can be used to store a single bit ofinformation. However, this information is notdirectly coupled to the semiconductors used toprocess information. Having a magnetic materialthat can store and process information wouldenable new forms of hybrid storage and processingcapabilities.Such a material has been created by the Pittresearch team led by Jeremy Levy, a DistinguishedProfessor of Condensed Matter Physics in Pitt'sKenneth P. Dietrich School of Arts and Sciencesand director of the Pittsburgh Quantum Institute.Levy, other researchers at Pitt, and colleagues atthe University of Wisconsin-Madison todaypublished their work in Nature Communications  ,elucidating their discovery of a form of magnetismthat can be stabilized with electric fields rather thanmagnetic fields. Working with a material formedfrom a thick layer of one oxide—strontiumtitanate—and a thin layer of a secondmaterial—lanthanum aluminate—these researchershave found that the interface between thesematerials can exhibit magnetic behavior that isstable at room temperature. The interface isnormally conducting, but by chasing away theelectrons with an applied voltage (equivalent to thatof two AA batteries), the material becomesinsulating and magnetic. The magnetic propertiesare detected using magnetic force microscopy, animaging technique that scans a tiny magnet overthe material to gauge the relative attraction orrepulsion from the magnetic layer.The newly discovered magnetic properties come onthe heels of a previous invention by Levy, so-called Etch-a-Sketch Nanoelectronics involving thesame material. The discovery of magneticproperties can now be combined with ultra-smalltransistors, terahertz detectors, and single-electrondevices previously demonstrated. This work is indeed very promising and may leadto a new type of magnetic storage, says StuartWolf, head of the nanoSTAR Institute at theUniversity of Virginia. Though not an author on thispaper, Wolf is widely regarded as a pioneer in thearea of spintronics. Magnetic materials tend to respond to magneticfields and are not so sensitive to electricalinfluences, Levy says. What we have discoveredis that a new family of oxide-based materials cancompletely change its behavior based on electricalinput. Provided by University of Pittsburgh  1 / 2    APA citation: New discovery could pave the way for spin-based computing (2014, September 25) retrieved27 September 2014 from This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Pwred byTCD  2 / 2    Spin-based electronics: New materialsuccessfully tested 30 July 2014  Hugo Dil and Nan Xu with their lab equipment at thePaul Scherrer Institute Credit: ©2014 EPFL Spintronics is an emerging field of electronics,where devices work by manipulating the spin ofelectrons rather than the current generated by theirmotion. This field can offer significant advantagesto computer technology. Controlling electron spincan be achieved with materials called 'topologicalinsulators', which conduct electrons only acrosstheir surface but not through their interior. Onesuch material, samarium hexaboride (SmB6), haslong been theorized to be an ideal and robusttopological insulator, but this has never beenshown practically. Publishing in Nature Communications  , scientists from the Paul ScherrerInstitute, the IOP (Chinese Academy of Science)and Hugo Dil's team at EPFL, have demonstratedexperimentally, for the first time, that SmB6 isindeed a topological insulator. Electronic technologies in the future could utilizean intrinsic property of electrons called spin, whichis what gives them their magnetic properties. Spincan take either of two possible states: up or down , which can be pictured respectively asclockwise or counter-clockwise rotation of theelectron around its axis.Spin control can be achieved with materials calledtopological insulators, which can conduct spin-polarized electrons across their surface with 100%efficiency while the interior acts as an insulator.However, topological insulators are still in theexperimental phase. One particular insulator,samarium hexaboride (SmB6), has been of greatinterest. Unlike other topological insulators, SmB6'sinsulating properties are based on a specialphenomenon called the 'Kondo effect'. The Kondoeffect prevents the flow of electrons from beingdestroyed by irregularities in the material'sstructure, making SmB6 a very robust and efficienttopological 'Kondo' insulator.Scientists from the Paul Scherrer Institute (PSI), theInstitute of Physics (Chinese Academy of Science)and Hugo Dil's team at EPFL have now shownexperimentally that samarium hexaboride (SmB6)is the first topological Kondo insulator. Inexperiments carried out at the PSI, the researchersilluminated samples of SmB6 with a special type oflight called 'synchroton radiation'. The energy ofthis light was transferred to electrons in SmB6,causing them to be ejected from it. The propertiesof ejected electrons (including spin) were measuredwith a detector, which gave clues about how theelectrons behaved while they were still on thesurface of SmB6. The data showed consistentagreement with the predictions for a topologicalinsulator. The only real verification that SmB6 is atopological Kondo insulator comes from directlymeasuring the electron spin and how it's affected ina Kondo insulator , says Hugo Dil. Although SmB6shows insulating behavior only at very lowtemperatures the experiments provide a proof ofprinciple, and more importantly, that Kondotopological insulators actually exist, offering anexciting stepping-stone into a new era oftechnology.  1 / 2    More information:   Nature Communications  , 30Jul 2014 DOI: 10.1038/ncomms5566Provided by Ecole Polytechnique Federale deLausanneAPA citation: Spin-based electronics: New material successfully tested (2014, July 30) retrieved 23September 2014 from This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Pwred byTCD  2 / 2
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