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Magnetic SemiconductorMagnetic semiconductors are materials that exhibit both ferromagnetism (or a similar response) and useful semiconductor properties. If implemented in devices, these materials could provide a new type of control of conduction. Whereas traditional electronics are based on control of carrier charge (n- or p-type), practical magnetic semiconductors would also allow control of quantum spin state (up or down). This would theoretically provide near-total spin polarization (as opposed to iron and other metals, which provide only ~50% polarization), which is an important property for spintronics applications. While many traditional magnetic materials, such as magnetite, are also semiconductors, materials scientists generally predict that magnetic semiconductors will only find widespread use if they are similar to well-developed semiconductor materials. To that end, dilute magnetic semiconductors have recently been a major focus of magnetic semiconductor research. These are based on traditional semiconductors, but are doped with transition metals instead of, or in addition to, electronically active elements. Hideo Ohno of Tohoku University did pioneering work in manganese doping of compound semiconductors such as indium arsenide and gallium arsenide. However, since these materials are not expected to produce Curie temperatures above room temperature, focus has shifted toward other materials such as gallium nitride.
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