Magnetocurrent in a bipolar spin transistor at room temperature

Abstract

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 1mA at a magnetically parallel state to 0.968mA at a magnetically antiparallel state. At the same states the base currents were 29.3μA and 333nA, 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.