Giant Magnetoresistance

Giant Magnetoresistance (GMR) is a quantum effect where a tiny change in a magnetic field causes a significant change in a material’s electrical resistance. This happens in layered structures of magnetic and non-magnetic materials. When magnetic layers are aligned with the magnetic field, electrons pass through more easily, reducing resistance. When they are misaligned, resistance increases. GMR enables highly sensitive magnetic sensors and is crucial for modern hard drive technology, allowing data to be read quickly and stored densely by detecting small magnetic changes.