A linear (or substantially linear) magnetoresistance sensor is provided. The magnetoresistance sensor may use one of the following magnetotransport mechanisms: classical magnetoresistance (MR) or quantum MR effects. In the classical regime, the sensor may be composed of a polycrystalline narrow gap semiconductor that has a varying mobility (instead of a constant mobility). The material's varying mobility enables the magnetoresistive sensor to have: (1) a linear magnetoresistance; (2) a high temperature response; and (3) an ability to respond to the highest possible fields. In the quantum regime, the sensor may be composed of a single crystal narrow gap semiconductor that is sufficiently doped so that the material may exhibit a linear response in a temperature range of 50K-175 K.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with government support under DE-FG02-99ER45789 awarded by the U.S. Department of Energy. The government has certain rights in the invention.