Spintronics - A New Hope for the Digital World

In our electronic world, since the discovery of electron by J J Thomson in 1897, scientists have been working strenuously to build the Digital World that we enjoy today. To satisfy a common man‘s need, researchers have been scratching the very basis of electronics – ̳Electron‘. All that we are using today is the flow of a bundle of electrons to determine the electronic outcome instead of the basic property of electron, which is to ̳Spin‘. They started exploiting this property leading to the rise of a new technology – Spintronics. Spintronics came into lime light in 1988 when French and German physicists Albert Fert et al (in Paris) and Peter Grunberg et al (in Jullich) independently discovered the Giant Magneto Resistance (GMR). This discovery is considered to be the birth of spintronics. The two physicists have earned a number of prestigious prizes and awards for their discovery and contribution in the field of spintronics, including the 2007 Noble Prize in Physics. Spintronics is based on the spin of electrons existing in one of the two states, namely spin up and spin down, with spin either positive half or negative half. In other words, an electron can rotate either clockwise or anti-clockwise around its own axis with constant frequency. The two possible spin states naturally represent ̳0‘ & ̳1‘ in logical operations. All spintronic devices act according to the simple scheme: (1) information is stored (written) into spins as a particular spin orientation (up, down); (2) the spins, being attached to mobile electrons, carry information along a wire and; (3) the information is read at terminal. The two important effects based on spintronics are the Giant Magneto Resistance (GMR) Effect and Tunnel Magneto Resistance (TMR) Effect, where GMR is the ferromagnetic alloy sandwiched around an ultra-thin non-magnetic middle layer. In this, the resistance changes depending on whether the moment of magnetic layer are parallel (low resistance) or anti-parallel (high resistance) while the TMR is a magneto resistive effect that occurs in magnetic tunnel junction. The various spintronic devices based on the above two effects are GMR sensor, spin valve, MRAM (Magneto resistive RAM), disks read / write heads of a disk drive, magnetic field sensors and one of the most promising aspects is quantum computers, where electron spin would represent a bit – called qubit – of information. These devices find a variety of applications in the field of automobile, telecommunication and in various electronic gadgets. This technology promises cheaper, compact and faster electronic gadgets. There are certain challenges in this technology concerning the detection of spin of electron, controlling the spin of electron and transferring the spin of electron under which research is still in progress. This technology has great potential to spin the global village into a technological revolution.