GMR heads for hard drives won the Nobel Prize in Physics
It became known yesterday that the Nobel Prize in Physics was awarded for the discovery of the effect of super magnetoresistance (GMR), which made it possible to create more sensitive magnetic heads for hard disks and significantly increase the recording density on the HDD.
The existence of the GMR effect was independently discovered in 1988 by the French physicist Albert Fert and his German colleague Peter Grunberg. They found that for samples of iron and chromium with a clear crystal structure, placed in a strong magnetic field, the electrical resistance sharply increases (see diagram). This is due to the exact mismatch spin electrons in the substance with the magnetic field direction.
This effect is the basis of the work of the GMR-sensor of the magnetic head of the hard disk. A special substance with GMR properties is embedded in the sensor head and increases its sensitivity. More effect can be seen on IBM learning animations .
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In the late 80s, IBM was the only one who instantly reacted to the discovery of Fert and Grünberg and immediately began active further research in this area, including the search for new materials suitable for use in hard drives and capable of operating in a weak magnetic field.
By 1991, IBM manufactured multilayer polycrystalline GMR samples obtained by spraying. At the same time, samples of GMR structures sensitive to weak magnetic fields, which are created by the magnetic surface of a hard disk, were developed. In 1994, IBM created the world's first HDD sensor element based on the GMR effect. GMR discs began mass production in December 1997. The first was a 3.5-inch Deskstar 16GP disc with a recording density of 2.69 Gbit / sq. inch.
The following year, IBM announced the creation of an experimental GMR-head with a recording density of 11.6 Gbit / sq. inch. But she was never allowed into mass production. Experts are of the opinion that this was due to marketing technologies, that is, a too sharp jump in HDD quality is not beneficial for manufacturers as long as they can make money with old equipment.
In other words, GMR technology is decades ahead of its time and is likely to be in demand for many more years. For this reason alone, its importance cannot be overestimated.
Moreover, since the technology made it possible to easily capture the spin of electrons in a substance, it gave rise to a fundamentally new direction of information technology - spintronics, which involves the use of electron spins as the minimum units of information exchange (0 and 1).
The existence of the GMR effect was independently discovered in 1988 by the French physicist Albert Fert and his German colleague Peter Grunberg. They found that for samples of iron and chromium with a clear crystal structure, placed in a strong magnetic field, the electrical resistance sharply increases (see diagram). This is due to the exact mismatch spin electrons in the substance with the magnetic field direction.
This effect is the basis of the work of the GMR-sensor of the magnetic head of the hard disk. A special substance with GMR properties is embedded in the sensor head and increases its sensitivity. More effect can be seen on IBM learning animations .
')
In the late 80s, IBM was the only one who instantly reacted to the discovery of Fert and Grünberg and immediately began active further research in this area, including the search for new materials suitable for use in hard drives and capable of operating in a weak magnetic field.
By 1991, IBM manufactured multilayer polycrystalline GMR samples obtained by spraying. At the same time, samples of GMR structures sensitive to weak magnetic fields, which are created by the magnetic surface of a hard disk, were developed. In 1994, IBM created the world's first HDD sensor element based on the GMR effect. GMR discs began mass production in December 1997. The first was a 3.5-inch Deskstar 16GP disc with a recording density of 2.69 Gbit / sq. inch.
The following year, IBM announced the creation of an experimental GMR-head with a recording density of 11.6 Gbit / sq. inch. But she was never allowed into mass production. Experts are of the opinion that this was due to marketing technologies, that is, a too sharp jump in HDD quality is not beneficial for manufacturers as long as they can make money with old equipment.In other words, GMR technology is decades ahead of its time and is likely to be in demand for many more years. For this reason alone, its importance cannot be overestimated.
Moreover, since the technology made it possible to easily capture the spin of electrons in a substance, it gave rise to a fundamentally new direction of information technology - spintronics, which involves the use of electron spins as the minimum units of information exchange (0 and 1).
Source: https://habr.com/ru/post/14901/
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