Spin-Dependent Tunneling: A New Magnetic Sensing Technology

摘要

Quantum mechanical tunneling, when combined with magnetic scattering due to the spin of electrons, results in an exciting new phenomenon called spin-dependent tunneling. Sensors based on this property will doubtless enter the commercial arena within the next two years. A new technology based on magnetic random access memory research is finding fertile ground in magnetic field sensing for applications that require very small size, low cost, and high sensitivity to small changes in the magnetic field. Many of today's solid-state sensor technologies rely on changes in resistance to provide a measure of change in the property to be measured, such as with RTDs, piezoresistive-based pressure sensors and accelerometers, and Hall and magnetoresistive sensors. Other sensors rely on resistance change due to the external stimulations of a semiconductor, e.g., the photoelectric effect. The mechanism described in this article is based on the conduction of electrons through an insulator.