Seminar Topic : Spintronics

ADICHUNCHANAGIRI INSTITUTE OF TECHNOLOGY

Seminar topic : Spintronics

Submitted by Mazher Pasha 4ai07ec053 A.I.T SPINTRONICS

Abstract: Spintronics is a rapidly emerging field of science and technology that will most likely have a significant impact on the future of all aspects of electronics as we continue to move into the 21st century. Spintronics is an interdisciplinary field in which the central idea is the manipulation of spin degrees of freedom in solid state systems. The motivation to examine semiconductor spintronics is stimulated by recent materials advances in magnetic semiconductors and the prospect of device applications, either not feasible or ineffective with conventional electronics. Conventional electronics are based on the charge of the electron. Attempts to use the other fundamental property of an electron, its spin, have given rise to a new, rapidly evolving field, known as spintronics, an acronym for spin transport electronics that was first introduced in 1996 to designate a program of the U.S. Defense Advanced Research Projects Agency (DARPA). The reviews of spin-polarized transport in bulk and low-dimensional semiconductor structures show promise for the creation of a hybrid device that would combine magnetic storage with gain-in effect, a spin memory transistor.

High-volume information-processing and communications devices are at present based on semiconductor devices, whereas information-storage devices rely on multilayers of magnetic metals and insulators. Switching within information-processing devices is performed by the controlled motion of small pools of charge, whereas in the magnetic storage devices information storage and retrieval is performed by reorienting magnetic domains (although charge motion is often used for the final stage of readout). Semiconductor spintronics offers a possible direction towards the development of hybrid devices that could perform all three of these operations, logic, communications and storage, within the same materials technology. By taking advantage of spin coherence it also may sidestep some limitations on information manipulation previously thought to be fundamental. This article focuses on advances towards these goals in the past decade, during which experimental progress has been extraordinary. Advantages:

The various advantages of Spintronics are as follows: - Spintronics does not require unique and specialised semiconductors, therefore it can be implemented or worked with common metals, such as Copper, Aluminium and Silver.

- Spintronics devices would consume less power compared to conventional electronics, because the energy needed to change spin is a easy compared to energy needed to push charge around. - Since Spins don`t change when power is turned off, the memory remains non-volatile. - Switching time is very less.

Applications:

 GMR sensors find a wide range of applications.  Fast and accurate position and motion sensing of mechanical components in precision engineering and robotics.  Missile Guidance.  Position and motion sensing in computer video games.  Key Hole Surgery and post operative care.  Automotive sensors for fuel handling system, speed control and navigation etc.  The Magnetic version of RAM used in computer is nonvolatile.  Other advantages of MRAM’s include small size, lower cost, faster speed and less power consumption, robust in extreme condition such as high temperature, high level radiation and interference.

References:

 Kevin Edmonds, Kaiyou Wang, Richard Campion School of Physics & Astronomy, University of Nottingham.

 Das Sarma, S., et al. 2001. Spin electronics and spin computation. Solid State Communications 119:207.

 Bennett, C. H., and D. P. DiVincenzo. 2000. Quantum information and computation. Nature (404):267.  G Tatara(Tokyo) & J. Shibata(Kanagawa), Hiroshi Kohno (Osaka University).  Institute of Solid State Physics, University of Tokyo.

 Josh Schaefferkoetter, “Introduction to Spintronics” (February 2007).