Spintronics
Introduction
Spintronics, also known as spin electronics, is a branch of physics that studies the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices. Spintronics fundamentally differs from traditional electronics in that, in addition to charge state, electron spins are exploited as a further degree of freedom, with implications in the efficiency of data storage and transfer. Spintronic systems are most often realized in dilute magnetic semiconductors (DMS) and Heusler materials, but can also be realized in organic semiconductors.
History
The history of spintronics can be traced back to the discovery of electron spin by Samuel Goudsmit and George Uhlenbeck in 1925. However, the term "spintronics" was coined much later, in the 1980s, following the development of spin-dependent tunneling (SDT) and the giant magnetoresistance (GMR) effect. The discovery of GMR, which is a quantum mechanical magnetoresistance effect observed in multilayers composed of alternating ferromagnetic and non-magnetic conductive layers, earned Albert Fert and Peter Grünberg the 2007 Nobel Prize in Physics.
Fundamentals of Spintronics
The fundamental concept of spintronics is the spin of the electron, which is a type of angular momentum intrinsic to particles. The spin can be up or down, and this gives rise to a magnetic moment and magnetic field. In a magnetic field, the electron's spin can be aligned in two directions (often termed spin up and spin down). The manipulation of spin in spintronic devices is achieved by making use of the spin-orbit interaction, which is the interaction of an electron's spin with its motion.
Spintronic Devices
Spintronic devices are electrical devices that use the spin of the electron to store, process and communicate information. They are an alternative to conventional electronic devices, which use the charge of the electron to process information. Examples of spintronic devices include spin valves, spin transistors, and spin-based quantum computing devices. These devices have the potential to increase the efficiency of data storage and transfer, and to reduce the power consumption of electronic systems.
Applications of Spintronics
The applications of spintronics are vast and varied. They range from data storage and magnetic sensing to quantum computing and medical imaging. In the field of data storage, spintronics is used in hard disk drives and random access memory (RAM). In the field of magnetic sensing, spintronic sensors are used to read data in hard disk drives. In the field of quantum computing, spintronics is used to create qubits, the fundamental units of quantum information. In the field of medical imaging, spintronics is used in magnetic resonance imaging (MRI).
Future of Spintronics
The future of spintronics is promising, with many exciting developments on the horizon. One of the most promising areas of research is the development of spin-based quantum computing, which could revolutionize the field of computing. Other areas of research include the development of spin-based light-emitting diodes (LEDs) and lasers, and the use of spintronics in the field of renewable energy.