Researchers at MIT have developed a new way to control the movement of the magnetic domains is the key technology of magnetic memory systems such as computer hard disk. The new approach requires little energy to burn and no power to maintain the stored information and could lead to a new generation of extremely low energy storage.
The new approach, applying a voltage controlled magnetism, not in a magnetic field. This can lead to a magnetic storage in which data is written to the microscopic Nanowires with magnetic tracks, or "bits" of data, hurtling along them as cars on the racetrack. The new findings, described in an article published this week in the journal Nature Nanotechnology, written by Associate Professor of materials science and engineering, and graduate student Jeffrey Beach Uwe Bauer and Satoru Emori.
"For hundreds of years, if you had a magnetic material, and you wanted to change the direction that was magnetized materials, you need another magnet," explains Beach. His work represents a whole new way to switch the magnetic State, using only the changes in voltage, without a magnetic field — a process much lower power consumption. Moreover, the magnetic switches when it keeps this change, ensuring stable data storage requiring no power except during reading and writing.
The researchers suggest that this effect can be used to include new concepts such as "racetrack memory," with the magnetic bits, speeding up the magnetic stripe. Although the laboratory demonstration of such devices, no one came close to viability for data storage: the missing piece was a way to precisely control position and select the individual electrically magnetic bits, racing along the magnetic stripe.
"Magnetic fields, it is very difficult to localize," Beach says: If you are trying to create a tiny magnetic bits on the area or Trek, the magnetic fields of electromagnets that are used to read and write data tend to spread out, making it difficult to prevent interaction with neighboring bands, especially, as the devices are getting smaller and smaller.
However, the new system accurately, you can select individual magnetic bits represented by tiny domains in the area. MIT device can stop the movement of magnetic domains, racing at 20 meters per second, or about 45 mph., "on a dime," said Beach. They can then be released on demand by simply switching the applied voltage.
To achieve this feat, the MIT team built a new type of device that controls the magnetism in the same way as transistor controls the flow of electricity. The key element is a layer of material Ion-rich, in which atoms have been stripped of electrons, leaving them with electric charge. Voltage to a small electrode above the thin layer can attract or repel these ions; ions, in turn, you can modify the properties of the base magnet and stop the flow of magnetic domains. The researchers suggest that this could lead to a new family of "magnetic ion" devices.
The effect depends on the chemical interactions between thin layers of magnetic metal and solid-state electrolyte materials sandwiched together at the border, Beach said. "So it's really a chemistry of interphase, which defines magnetic properties," he said. In practice, such a system would use wire or strip of ferromagnetic material with a series of regularly spaced, small electrodes on top of it. Magnetic bits between these electrodes can then selectively written or read.
After you specify the orientation of the magnetic bits between the two electrodes of the device "it essentially will retain his position even in the absence of power and direction," Beach said. Thus, in practice, you can install the magnetic bits, "then turn off until you need to read it back," he said. Because the magnetic switch requires no magnetic field, there is next to no dissipation of energy, "said Beach. What's more, by pinning of magnetic bits is extremely strong, resulting in stable storage.
The key components of the system are "very simple oxide materials," says Bauer. In particular, these tests are used gadolinium oxide, which is already used in capacitors and semiconductors. Dan Allwood, a researcher in materials physics at the University of Sheffield, who was not involved in the study, said that he "not only offers a Novel technical ways to manage dynamic magnetization patterned nanostructures, but also presents new physical processes in how stress can affect the magnetic behavior in General. Detailed understanding of the origin of these effects may allow the creation of simple, low-power information and technological devices. "
In addition to magnetic storage systems, the MIT team says this technology could also be used to create new electronic devices based on spintronics, in which information is provided spin orientation of atoms. "This opens up a whole new domain," said Beach. "You can do data storage and calculations, potentially at a much lower power consumption.