von Klitzing, Klaus (1943– )

German physicist who was awarded the Nobel Prize for Physics in 1985 for his discovery of the quantized Hall effect. This effect involves the behaviour of electric currents in thin films of material held in a strong magnetic field at a low temperature. If the magnetic field is varied, the current changes in a step-like fashion, rather than in a smooth regular way. This steplike behaviour indicates that quantum effects are taking place. The quantized Hall effect is one of the few situations where quantum effects can be studied using ordinary macroscopic measurements. The effect is used to make very accurate measurements of electrical voltages.

Von Klitzing was born in Schroda (Posen). He studied physics at the Technical University of Braunschweig and at the University of Würzburg, gaining his doctorate in 1972. He became a professor at the Technical University at Munich in 1980. In 1985 he was appointed director of the Max Planck Institute, Stuttgart.