1994, IBM developed a read head with giant magnetoresistance effect, which suddenly increased the recording density of the disk by 17 times, reaching 5Gbit/in2, and recently reached 1 1Gbit/in2, thus making the disk once again in the leading position in the competition with optical disks. Due to the giant magnetoresistance effect, the device is easy to be miniaturized and the price is low. In addition to reading the magnetic head, it can also be used as a sensor for measuring displacement and angle, and can be widely used in CNC machine tools, automobile speed measurement, non-contact switches and rotary encoders. Compared with photoelectric sensor, it has the advantages of low power consumption, high reliability, small size and can work under harsh working conditions. Random access memory (MRAM) can be made by using the characteristic that giant magnetoresistance effect has different resistance values in different magnetization states. Its advantage is that it can continue to retain information without power supply.
Another important aspect of giant magnetoresistance effect in high-tech field is weak magnetic field detector. With the rapid development of nano-electronics, miniaturization and high integration of electronic components require miniaturization of measurement system. In the 2 1 century, superconducting quantum coherent devices, ultramicro Hall detectors and ultramicro magnetic field detectors will become the protagonists of nanoelectronics. Among them, the design of ultra-micro magnetic field sensor based on giant magnetoresistance effect requires that it can detect the magnetic flux density from 10-2T to 10-6T. It was impossible to measure such a low magnetic flux density in the past, especially in the ultra-micro system. Nanostructured giant magnetoresistance devices can accomplish this task.
The Royal Swedish Academy announced on the 9th that the 2007 Nobel Prize in Physics will be awarded to French scientist Albert Fell and German scientist peter green Berg for their discovery of the giant magnetoresistance effect. They will share the prize of 1 00000 Swedish kronor (1US$ 7 Swedish kronor). The Swedish Academy of Royal Sciences said: "This year's physics prize was awarded to the technology of reading hard disk data. Thanks to this technology, hard disks have rapidly become smaller and smaller in recent years. "
Usually, a hard disk is also called a magnetic disk because magnetic media is used to store information in the hard disk. Generally speaking, there are several disks in a sealed hard disk cavity, and each side of each disk is divided into multiple tracks with a certain magnetic density as the axis, and each track is further divided into several sectors. Each disk surface of a magnetic disk has a corresponding data reading head.
To put it simply, when the data reading head "scans" all areas of the disk surface, the different magnetic signals recorded in all areas are converted into electrical signals, and the changes of the electrical signals are further expressed as "0" and "1", which becomes the original "decoding" of all information.
With the wave of information digitization, people began to seek the technology of continuously reducing the size and increasing the capacity of hard disks. 1988, Phil and Gruenberger independently discovered the "giant magnetoresistance" effect, that is, a very weak magnetic change can cause a great change in resistance.
This discovery has solved the biggest problem of manufacturing large-capacity and small-sized hard disks: when the volume of hard disks is getting bigger and bigger, it is inevitable that each divided independent area on the disk will become smaller and smaller, and the magnetic signals recorded in these areas will become weaker and weaker. With the help of "giant magnetoresistance" effect, people can make more sensitive data reading heads, so that weaker and weaker magnetic signals can still be clearly read and converted into clear current changes.
1997, the first data read-out head based on "giant magnetoresistance" effect came out, which quickly triggered the revolution of "large capacity and miniaturization" of hard disk. At present, the hard disks equipped in various digital electronic products such as notebook computers and music players have basically applied the "giant magnetoresistance" effect, and this technology has become a new standard.
According to the Scientific Bulletin of the Royal Swedish Academy, another technology invented in the 1970s, that is, the technology of making ultra-thin layers of different materials, made it possible for people to make thin layers with a thickness of only a few atoms. As the data read-out head is composed of multiple layers of thin films of different materials, as long as the "giant magnetoresistance" effect is still effective, scientists can further reduce the volume and increase the capacity of hard disks in the future. Both scientists like music. Phil's favorite musician is American jazz pianist thelonious monk, while Gruenberg loves classical music. He is also a guitar lover.
Phil/Kloc-0 was born in March, 1938 in Carcassonne, a small town in southern France. 1970 received his Ph.D. degree from Paris Nantes University, and 1976 became a professor at Paris Nantes University. Since 1995, Phil has also served as the scientific director of the joint physics laboratory established by the French National Research Center and France-Guotai Reyes Group. Phil was elected as an academician of the French Academy of Sciences in 2004.
Gruenberg/Kloc-0 was born in Bilsen in 1939, received his Ph.D. from Darmstadt University of Technology in 1969, became a professor at the German ulrich Research Center in 1972, and retired in 2004.
Gruenberg has a strong awareness of intellectual property protection. When two scientists discovered the "giant magnetoresistance" effect in 1988, they realized that this discovery might have a huge impact. Gruenberg also applied for a patent for this.
At present, the small-capacity and large-capacity computer hard disks developed according to this effect have been widely used. The two scientists have previously won many scientific awards for discovering the "giant magnetoresistance" effect.