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The magical journey of magnetic tunnel structures: How to realize electron tunneling through thin insulating layers?
In today's world of microelectronics and spintronics, the concept of magnetic tunnel junctions (MTJs) seems to be a miracle of technological progress. With the rapid development of science and technology, the potential of MTJ has attracted more and more attention, especially in data storage and sensor technology. This article will investigate the structure's physical basis, historical context, and future potential, and explore why this technology has attracted so much attention.
Magnetic tunneling is a quantum mechanical phenomenon that allows electrons to tunnel through a thin insulator to another electrode, even though this is a forbidden behavior in traditional physics.
Overview of Magnetic Tunneling Effect
The magnetic tunnel effect (TMR) occurs in a magnetic tunnel structure, which is a structure consisting of two ferromagnets and a thin layer of insulator. If the insulator is thin enough (usually only a few nanometers thick), electrons can tunnel between the two ferromagnets. When the two magnets are magnetized in the same direction, the probability of electron tunneling increases, but when their magnetizations are in opposite directions, this probability decreases significantly.
The current study shows that there is a significant difference in resistance between the two magnetic electrodes of the tunnel structure, which allows the electronic device to switch between low and high resistance.
MTJ's History
The magnetic tunneling effect was first discovered in 1975 by Michel Jullière of France in the Fe/Ge-O/Co structure. Although the resistance change was only 14% at the time, the discovery did not attract widespread attention. Interest expanded until 1994, when researchers observed resistance changes of up to 70% with the combination of ferromagnetic electrodes and amorphous aluminum oxide insulators. In 2001, Butler and Mathon first predicted that using magnesium oxide (MgO) as an insulator, resistance changes of up to several thousand percent could be achieved.
With the development of MgO materials, the resistance change rate of MTJs has been greatly improved, making them more important in various electronic applications.
Physical Mechanism and Its Applications
The physical mechanism of TMR involves the spin polarization of ferromagnetic electrodes. The two electrodes can show their spin characteristics during the tunneling process, resulting in different spin states having different transmittances to electrons. Such properties make possible modern data storage technologies such as MRAM (magnetoresistive random access memory), which can retain data even when there is no power supply.
Today, magnetic tunnel structures are widely used in the read heads of modern hard disk drives and in position and current sensors in automotive, industrial and consumer electronics. Due to their improved performance, these high-performance sensors are gradually replacing traditional Hall sensors.
ConclusionIn the future, with the rapid advancement of technology, the development of MTJ is expected to play an important role in more emerging fields such as quantum computing and high-speed data processing.
The development of magnetic tunnel structures not only demonstrates the importance of quantum mechanics in practical applications, but also promotes the advancement of information technology. With the deepening of research and the emergence of new materials, the application scope of MTJ is still expanding. Looking to the future, this technology can theoretically achieve higher data storage density and faster reading speeds. So, what kind of changes will future technology face due to this quantum phenomenon?
