The IBM 5100, the first commercially available portable computer, appeared in 1975, Audio Highway won an Innovations Award at the Consumer Electronics Show in 1997 for their “Listen up” MP3 player, and Apple launched their colored iMac G3 in 1998.


Although these devices were a state of art, we had only seen a start of devices that got smaller, smarter and faster for each year. Today, most people have their laptop in their smartphone, a LCD-TV not thicker than an inch and the wristwatch can be turned into an mp3 player- But where does it stop?

The age of electrically-based transistors -  a semiconductor device used to amplify and switch electronic signals and power - has been with us for more than six decades. The conventional way of improving the functionality of transistors remained the traditional downscaling of device dimension. However, in the near future the existing device architectures, as well as material properties will reach their fundamental limitations for downscaling, i.e. the computer cannot get much smaller. Also, volatile memory, which does not retain information upon being powered off, is significantly hindering ultrafast computing speeds. -Is there a solution in the future

Chalmers Assistant Professor Saroj Dash believes it is, and a new breed of electronics, dubbed “spintronics”, may be the necessary solution. Instead of solely relying on the electron’s charge to manipulate its motion or to store information, spintronic devices would further rely on the electrons spin degree of freedom. The advantage of spin-based electronics is that they are very nonvolatile -retain the stored information even when not powered - compared to charge based electronics. Quantum-mechanical computing based spintronics could therefore achieve speeds unheard of with conventional computing can. 

The electron spin is either +1/2 or -1/2, in other words, an electron can rotate either clockwise or anti-clockwise around its own axis.

The new technology based on spintronics would allow a new high-performance generation of computing that requires far less power than conventional ones -possibly what for a long time has been addressed as ultra-fast, futuristic, “quantum computers”. Spin-based technologies may have a further profound impact on nanoelectronics, data storage, and logic & computer architectures.

The use of electron spin has already led to many fascinating physical phenomenon and continues to produce more. Spin transport in metal system have demonstrated the potential these phenomena have in electronic technology in the form of, i.e. magnetic read head (in computer Hard Disks) and magnetic random access memory (MRAM). Read heads use GMR (giant magnetoresistance) and TMR (tunnel magnetoresistance) sensors in memory devices of computers and mobile phones. In hard disks, these GMR and TMR read heads have enormously enhanced read and write speed and data storage capacity. Peter Grünberg and Albert Fert were awarded "2007 Nobel Prize in Physics" for the discovery of GMR effect”, Saroj says.

Spin based- Magnetic Random Access Memory (MRAM), a fast emerging next generation memory device.

The recent effort, which is more radical, focuses on finding novel ways of both generation and utilization of spin-polarized currents in semiconducting materials. A recent advancement in the process of semiconductor spintronics was made by Saroj before his time at Chalmers, rather at University of Twente in Enschede, Netherlands. Saroj and his colleagues successfully achieved a spin injection in silicon at room temperature - published in Nature, November 26, 2009. Something that only has been accomplished at minus 150 Celsius degrees before. The interest in integration of silicon into ferromagnetic materials stems from its long spin coherence time and length. This will allow the written information to be processed in integrated circuits and stored for longer time.
 

A proposed Spin Field Effect Transistor (Spin-FET)