Spintronics

 Electronics Vs Spintronics

One of the most inherent advantages of spintronics over electronics is that magnets tend to stay magnetised, which is sparking in the industry an interest for replacing computers’ semiconductor-based components with magnetic ones, starting with the random access memory (RAM), Let me tell you an example: You are in the mid of documenting a project presentation that you need to present tomorrow morning and you face an electric power failure. Your UPS was not recharged and, the worst part of all, you didn’t save your presentation. I am sure that a condition like this is enough, to leave you back, pulling your hair, for now you have to do the same task right from the scratch.

Spin-Valve Transistor

A new type of magnetic field sensor is the spin-valve transistor (Fig. 5). This transistor is based on the magneto resistance found in. multilayers (for example, in Co/Cu/Co). Usually, the resistance of a multiplayer is measured with the current-in-plane (CIP). The CIP configuration suffers from several drawbacks; for example, the CIP magneto resistance is diminished by shunting and diffusive surface scattering.

 Abstract

Control over spins in the solid state forms the basis for nascent spintronics and quantum information technologies. There is a growing interest in the use of electronic and nuclear spins in semiconductor nanostructures as a medium for the manipulation and storage of both classical and quantum information.

Spin-based electronics offer remarkable opportunities for exploiting the robustness of quantum spin states by combining standard electronics with spin-dependent effects that arise from the interactions between Sections, nuclei, and magnetic fields. Here we provide an overview of recent developments in coherent electronic spin dynamics in semiconductors ant quantum structures, including a discussion of temporally- and spatially-resolved magneto-optical measurements that reveal an interesting interplay between electronic and nuclear spins. In particular, we present an electrical scheme for local spin manipulation based on g¬tensor modulation resonance (g-TMR), functionally equivalent to electron spin resonance (ESR) but without the use of time dependent magnetic fields.

Magnetic sensitivity

The number of electrons that reach the collector increases exponentially with the mean free path of the electrons in the base. The mean free path varies with the applied magnetic field; hence the collector current becomes strongly magnetic field-dependent.

Spin Relaxation

Non-equilibrium spin accumulates in non-magnetic region due to process of spin injection. It comes to equilibrium by the phenomenon called spin relaxation . The rate of accumulation of non-equilibrium spin depends on the spin relaxation. Electrons can remember their spin state for finite period of time before relaxing. That finite time period is called ‘Spin lifetime’. Longer lifetime is more desirable for data communication application while shorter for fast switching.

Conclusion

Spintronics is still in its infancy and it’s difficult to predict how it will evolve. New physics is being discovered and new materials are being developed, such as magnetic semiconductors and exotic oxides that manifest an even more extreme effect called colossal magneto resistance.