Peter Grünberg

Peter Grünberg (1939–2018) was a German physicist who shared the 2007 Nobel Prize in Physics for discovering giant magnetoresistance.

Albert Fert: French physicist who shared the 2007 Nobel Prize in Physics for discovering giant magnetoresistance. Fert independently discovered giant magnetoresistance in 1988, shortly before Grünberg’s group reported it.
Giant magnetoresistance: A large change in electrical resistance caused by changing the relative magnetization of magnetic layers. Grünberg discovered this effect in thin magnetic multilayers.
Molecular beam epitaxy: A vacuum technique that deposits crystalline films one atomic layer at a time. It enabled the precise iron and chromium layers in Grünberg’s experiment.
Read head: A sensor that detects magnetically encoded information on a storage medium. Giant magnetoresistance made highly sensitive read heads possible.
Helmut K. V. Lotsch: German physicist who led the Jülich research group where Grünberg studied magnetic materials. Lotsch supervised Grünberg’s doctoral work at the Jülich Research Centre.
Spin-dependent scattering: Electron scattering whose probability depends on the electron’s spin and the material’s magnetic orientation. Different scattering for aligned and opposed spins produces the resistance change Grünberg observed.
Neutron reflectometry: A method that probes thin-film structures and magnetization using reflected neutrons. Grünberg’s group used it to investigate magnetic coupling in multilayers.
Hard disk drive: A data-storage device that records information magnetically on rotating disks. Giant-magnetoresistance read heads enabled major increases in storage density.
Jülich Research Centre: German national research institution established in 1956 as a nuclear research center. Grünberg conducted the thin-film research there that led to his discovery.
Magnetic multilayer: A material built from alternating thin layers with different magnetic or nonmagnetic properties. Grünberg’s 1986 experiment used alternating iron and chromium layers.

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Magnetoresistive random-access memoryRelated: His discovery helped establish magnetic multilayers as useful electronic devices.