Spin Valve Transistor – Electronics of Modernized Computation

Computation and data transference is substantially advanced concepts in the contemporary era. Scientists and technologists now have to perform calculations that are beyond manual mathematics, usually done by classic computers.

Classic computing, with the help of conventional electronic devices, use semiconducting and magnetic materials for logical operations and storage respectively. However, modernized spintronic devices provide more versatility than conventional modern devices. One such device belonging to spintronics is Spin Valve Transistor (SVT). Here let us discuss the properties of Spin Valve Transistor and its working in the modern computational era.

What is a Spin Valve Transistor?

A Spin Valve Transistor is a bit different from your conventional transistor. SVT ensures that only correct spin-polarized electrons can travel through devices. Use of SVT device range from data storage, signal processing to robotics and automation. It has enough juice to produce results with substantially less power consumption and less heat. It is the core application of Quantum Computing, which is the future of computation in the contemporary era.

The Discovery of Spin Valve Transistor

Numerous scientists and technologists made ingenious discoveries on Giant Magnetoresistance (GMR) because of Spin Valve Transistor. Previously, resistance via magnetic multilayers consisted of shunt resistance and channeling, which reduced the overall magnetoresistance. The spin valve transistor acts as a base for a silicon-based transistor. Preferably, the metal-based transistors are used for ultrahigh-frequency operation; given that, it has low base resistance and negligible base transport time.

Structure of Spin Valve Transistor

The spin valve transistor consists of a couple of magnetic metal layers, disconnected with a non-magnetic metal layer. In the figure below, you will see that the magnetizations have anti-parallel alignment on the two magnetic layers. Here the minority spin electrons on the bottom magnetic layer are the majority spin electrons on the upper magnetic layer.

vv Spin valve transistor image 49939929919
(Source: http://www.ub.utwente.nl/webdocs/el/1/t000001d.pdf)

Operation of Spin Valve Transistor

For the device to get the spin-valve effect in a spin valve transistor, electrons go through a metallic base bridged across a Schottky barrier. The electrons impact the emitter side of the Schottky barrier, passes through the spin valve and reach the collector side of the transistor.

When the electrons enter impacts the metallic base electrons, releasing of hot electron energy takes place in Spin Valve Transistor. During the moment of impact, electrons get elastic and inelastic scattering, determined by emitter Schottky barrier height.

Effect on Electrons

During the release of hot electron energy, electrons can only enter the collector if they have enough energy, given that they have to break the energy barrier at the other end. Not to mention that the electrons can only enter the collector stage if they have some momentum as that present in the collector semiconductor.

Advantages of Spin Valve Transistors

  • Traditional transistors typically use on and off charges (0s and 1s of Binary information). However, spin field electrons use up and down states to generate the same binary data efficiently.
  • Previous transistors utilized conventional current (electrons), while Spintronics or Spin Valve transistors use current and store data as well.
  • Having charged electrons is a problem, given that more devices together heat up. In such circumstances, traditional transistors are ineffective. On the other hand, spin current releases less heat in comparison with old transistors.
  • You can also control the external magnetic field to the device by switching its properties.

Limitations of Spin Valve Transistors

  • It doesn’t work well for long distances.
  • Controlling spin on Spin Valve Transistors is difficult when we have a silicon-based semiconductor.

Hardayal (Harry) Gill has been part of the tech industry for over four decades, especially in the field of systems engineering. His immense knowledge in the industry makes him a brand in the technology industry. After graduating from the University of Minnesota, he has worked with numerous tech giants that are renowned globally. He has work experience with Hewlett Packard, Hitachi, and IBM Corporation.

Having experience in such a wide variety makes him a valuable asset in the field of technology and system designs. In addition to that, he has more than 320 US patents on Recording and memory components. He also has extensive skillsets comprising of magnetic thin film design and the concept of Spin Valve Transistors.


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