Types of Spintronics

There are four types of Spintronics:

• Giant Magnetoresistance (GMR)
• Spin Transfer Torque (STT)
• Metal-Based Spintronics
• Semiconductor-Based Spintronics

1. Giant Magnetoresistance (GMR)

The Giant Magnetoresistance is a quantum mechanical effect that was discovered independently by the Albert Fert and Peter Grünberg in late 1980s. In the given image, you would visualize layers of the magnetic materials separated by a non-magnetic spacer. The relative orientation of magnetization in the magnetic layers affects the electrical resistance. When the magnetization is parallel , resistance is lower and when it’s antiparallel resistance is higher. This groundbreaking discovery opened up new possibilities in field of the spintronics and revolutionized data storage technology.

2. Spin Transfer Torque (STT)

The given diagram shows a layered structure with a fixed magnetic layer and a free magnetic layer and separated by an insulating layer. A current carrying spin-polarized electrons is shown being injected into free layer and Depending on the relative orientation of the spins in two layers, the spin transfer torque can lead to switching the orientation of free layer.

3. Metal-Based Spintronics

Th Metal-based spintronics primarily involve the manipulation of the electron spin in metallic materials. This approach is often referred to as “giant magnetoresistance” or “spin-valve” technology.

• GMR Devices: The GMR devices consist of alternating layers of the ferromagnetic and non-magnetic metals. When an external magnetic field is applied the relative orientation of magnetic moments in ferromagnetic layers can change.
• Spin-Transfer Torque (STT): The STT is a phenomenon in which the spin of the electrons is transferred to magnetic moments in a material leading to changes in their orientations.

4. Semiconductor-Based Spintronics

The Semiconductor-based spintronics focuses on using the semiconducting materials such as silicon or organic semiconductors to manipulate electron spin. This field offers the potential for the combining traditional electronic logic with the spin-based functionalities.

• Spin Injection and Detection: In semiconductor-based spintronics spins are manipulated using the various techniques such as spin injection from the ferromagnetic contact into semiconductor and spin detection by the measuring spin-polarized electron current.

• Spin Transport: The semiconductor materials can support the transport of the spin-polarized carriers over longer distances.

• Spintronics in Logic and Memory: The Semiconductor-based spintronics can be integrated into the conventional semiconductor devices like transistors to create more energy-efficient logic circuits and non-volatile memory devices.

Spintronics, which stands for “spin transport electronics” is a branch of electronics that exploits the intrinsic spin of the electrons and their fundamental electronic charge for the various functionalities in solid-state devices. Unlike traditional electronics which rely solely on the charge of the electrons, spintronics utilizes both charge and spin properties for data storage, processing, and communication. Electron spins in Spintronics are used to represent binary data which enables efficient and faster data storage and data processing. It is also useful in creating devices that are energy efficient. One such example is a spin-based transistor which can reduce the consumption of power, leading to greener technology. In this article, we will study about Spintronics in detail.