The discovery was made independently by the Frenchman Albert Fert in 1988, and the German Peter Grünberg, although the technology did not take shape as such until the late 1990s.
GMR technology allows data to be read from very compact discs. This is the description of the Royal Swedish Academy of Sciences, which awards the Nobel prizes: “A hard disk stores information, such as music, in the form of small microscopic areas magnetized in different directions. The information is retrieved by a reading head that scans the disk and records magnetic changes. The smaller and more compact the hard disk, the smaller and closer the individual magnetic areas will be. “
“It is necessary to use more sensitive reading heads when the storage density on the hard disk increases. A reading head based on the GMR effect is capable of converting small magnetic changes into differences in electrical resistance and thus into changes in electrical resistance. current emitted by the reading head. The current is the signal obtained from the reading head and its different signal levels represent the ones and the zeros “.
Additional information on this discovery can be obtained here