Magnetic Tunnel Junctions

A Magnetic Tunnel Junction (MTJ) is a device made of two thin magnetic layers separated by an insulating barrier. Its electrical resistance changes depending on whether the magnetic moments of the layers are aligned parallel or antiparallel. When aligned parallel, it conducts electricity more easily; when antiparallel, it resists flow. This property allows MTJs to be used in magnetic sensors and memory devices, such as MRAM, where data is stored based on magnetic states. The key is quantum tunneling, where electrons pass through the insulating barrier depending on their spin, enabling fast and energy-efficient data storage and retrieval.