A magnetic semiconductor is a type of substance that is both semi-conductive and ferro-magnetic. Magnetic semiconducting materials produce forces of attraction similar to that of a normal magnet. Most ferromagnets such as iron are very electrically conductive; however, a magnetic semiconductor is neither completely conductive nor purely resistant. This unique combination of conductive and magnetic attributes makes the material useful in newer types of computers.
The study of magnetic semiconductors began in the 1970s and 1980s. During this time period, scientists observed several unknown electrical behaviors in metal and semiconductors. Observations of the magnetic semiconductor phenomenon led to the theory of "spintronics." This emerging field of computer science enables both the charge and spin direction of an electron to be controlled. While a traditional semiconductor, such as a transistor, can control only electrical charges, a magnetic semiconductor provides more precise manipulation of an electron's state.
Computers typically use semiconductors and electromagnets for separate functions. Semi-conductive material such as silicon chips are used for processing and calculations. Electromagnetic materials are often used for data storage, such as on the disks of a hard drive. Transferring data from the semiconducting processor to the magnetic storage is not instant, however. This time consuming data transfer is commonly seen when a computer is "booted up" and the operating system is loaded.
Using spintronics, a magnetic semiconductor would eliminate this buffer and dramatically increase the speed of computers. This type of material combines the functions of magnetic storage and semi-conductive processing, and allows information to be manipulated and stored on the same chip. A magnetic semiconductor computer can be booted instantly, since there is no need to load data from a separate storage device.
Temperature is one of the primary challenges in building magnetic semiconductor devices. Materials typically display both magnetic and semi-conductive behaviors at very low temperatures; this is a significant problem, since computers must be able to operate at room temperatures to be practical. Many scientists are experimenting with the combination of different substances, in order to create a material that is ferro-magnetic and semi-conductive at nominal temperatures.
These materials have other possible applications in addition to computer devices. Magnetic semiconductors can be useful in creating very accurate sensors. New sensors may be able to both detect and store important information on a single unit. The development of this technology can also be used for powerful and precise lasers, which may be useful in the field of medicine.