Magnetocurrent in a bipolar spin transistor at room temperature.

A spin transistor which consists of a metallic giant magnetoresistance emitter, a copper base, and a p-n junction was prepared on a Si(100) wafer. The emitter current changes from 1 mA at a magnetically parallel state to 0.968 mA at a magnetically antiparallel state. At the same states the base currents were 29.3 μA and 333 nA, respectively, which gave a magnetocurrent ratio of ∼8600% and a transfer ratio of 3×10-2 at room temperature for a common collector configuration. The sensitivity of this spin device is higher than 4000%/Oe. The memory effect and the high performance make it possible for practical usage. The working principle of this kind of three-terminal spin device can be simply described by circuit theory. [ABSTRACT FROM AUTHOR]