Spintronics is a nascent form of electronics which uses the magnetic state (spin) of electrons to encode and process data, rather than using electric charge. Technically, spin is a quantum property, closely related to but not exactly the same thing as magnetism. Spintronics is therefore sometimes regarded as exploiting quantum effects. An electron can possess either an up or down spin, depending on its magnetic orientation. The magnetism of ferroelectric materials, nonconductors which become polarized when exposed to an electric field, exists because many of the electrons in such objects all have the same spin.
Also known as magnetoelectronics, spintronics has the potential to become the ideal memory media for computing. It has been claimed that spintronic memory, or MRAM (Magnetoresistive Random Access Memory) has the potential to achieve the speed of SRAM (Static RAM), the density of DRAM (Dynamic RAM), and the non-volatility of flash memory. Non-volatility means that the data is still encoded when the power is shut off. Spintronics has also been called a step in the direction of quantum computing.
Because of its non-volatility, MRAM or other spintronics could one day be used to create instant on computers and extremely convenient memory, storage devices and batteries. The technology could also be used to create electronic devices which are smaller and faster and consume less power. It is projected that MRAM devices will be commercially available by 2010, with other spintronics devices following in the early teens.
The first widely acknowledged breakthrough in spintronics was the exploitation of giant magnetoresistance, or GMR, a technology now employed in the read heads of most hard drives. GMR and other spintronics can be used to detect extremely small magnetic fields by using a nonmagnetic material sandwiched between two magnetic plates. This material changes its electrical resistivity rapidly based on the magnetic orientation of the plates. GMR can be 100 times stronger than ordinary magnetoresistance. Sometimes GMR devices are referred to as spin valves.
Synthesizing MRAM-based devices can be convenient because the fabrication techniques involved have a lot in common with conventional silicon semiconductor fabrication techniques. Proposals for electronic/magnetic integrated devices are common. In 2002, IBM announced that they had achieved a storage capacity of one trillion bits per square inch in a prototype storage device.
