Spin valve

A schematic diagram of a so-called spin valve. The free layer consists of soft magnetic material, while the so-called fixed layer is hard magnetic . If the magnetic layers are oriented anti-parallel, the electrical resistance of the overall system is higher than if they are parallel (high resistance state versus low resistance state)

A spin valve is a technical device that is used, among other things, to measure and generate weak currents. It is based on the so-called GMR effect , for which Albert Fert and Peter Grünberg were awarded the Nobel Prize in 2007 : The device consists of an interconnection of two (or more) conductive magnetic materials. The electrical resistance of the overall system (e.g. from bottom to top) changes in a measurable order of magnitude when the relative orientation of the magnetization of both layers is switched from anti-parallel to parallel.

The expansion of the systems is in the microscopic range of a few micrometers (thousandths of a millimeter) or less.

Applications

Spin valves are used in the sensor technology of weak magnetic fields and in the computer industry in the so-called "read heads" of magnetic hard drives. They are also used in MRAMs .

See also

• Spintronics
• Magnetoelectronics

Individual evidence

1. ^ Spintronics Materials and Phenomena Research . Retrieved January 13, 2012.