Spintronics

Properties of Electron Electron has three properties. Charge Mass Spin

Conventional Electronics Conventional Electronic devices rely on the transport of electrical charge carriers. It utilizes only the charge and the mass of electrons.

Why Spintronics?  Moore’s Law: Number of Transistor doubles in every 18 months  Complexity: Complex Chip Design & Power Loss

What is Spintronics?  It deals with spin dependent properties of an electron instead of or in addition to its charge dependent properties.  It promises new logic devices which enhances functionality, high speed, reduced size and reduced power consumption.

Need for Spintronics Storage device of size of atom working at a speed of light Computer memory thousands of times denser and faster than today’s memories. Cancer cells detection even though they are small in number.

Principle Based on the spin of electrons rather than its charge Two spin states: spin-up and spin-down Spin makes an electron a tiny magnet with north and south poles.

Working The information is stored (written) into spins as a particular spin orientation (up or down). The spins, being attached to mobile electrons, carry information along a wire and the information is read at a terminal. Spin orientation of conduction electrons survives for relatively long time which makes spintronic devices useful for memory storage and magnetic sensor applications

GMR Magnetism is the integral part of data storage techniques. Data is stored as tiny areas of magnetized iron or chromium oxide. Magneto resistance is the property of a material to change the value of its electrical resistance when an external magnetic field is applied to it. GMR is more sensitive.

Spintronic Devices Some of the Spintronic devices are MRAM ( Magnetoresistive Random Access Memory) Spin Transistor Quantum Computer Spintronic Scanner

MRAM It is based on integration of MTJ (Magnetic Tunnel Junction). In this data is not stored as electric charge or current flow, but by Magnetic storage elements. Advantages of MRAM are that it is non volatile, small in size, lower cost, faster speed and less power consumption

Spin Transistor It is based on magneto resistance, found in multi layers (Co-Cu-Co) forming the base region. Traditional silicon chips-flow of electrical current is controlled by modifying the positive or negative charge. Spin transistor-spin is used to control the movement of currents.

Quantum Computer The basic principle behind quantum computation is that quantum properties can be used to represent data and perform operations on these data. A quantum computer maintains a sequence of qubits. Solve problems much faster.

Spintronic Scanner It is an efficient technique to detect cancer cells even when they are less in number. Exposing to strong magnetic field and passing electrons with polarized spin.

Electronics vs. Spintronics  No ‘boot-up’ waiting period required.  No need for specialized Semiconductors.  It can work with common metals like Cu, Al, Ag.  Less power consumption than conventional electronics.  Non-volatility.

Conclusion With lack of dissipation, Spintronics may be the best mechanism for creating ever-smaller devices. The potential market is enormous, In maybe a 10- year timeframe, Spintronics will be on par with electronics. That's why there's a huge race going on around the world In exploring Spintronics.

References mechanisms of spin relaxation in electronic systems (metals and semiconductors) in J. Fabian and S. Das Sarma, J. Vac. Sc. Technol. B 17, 1708 (1999).

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