Faster Data Storage Possible With New Method of Controlling Magnets

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The more common magnets people are familiar with are made of ferromagnetic materials, with their atoms’ north-south magnetic axes line up in the same direction. Thus, the collective force of the magnet is strong enough to create substantial attraction. Currently, these materials are the basis for most of the data storage devices available today.

Ferrimagnetic materials

However, ferrimagnetic materials are also available, but they are less common. In this type of material, some atoms line up in one direction while the others align in the opposite direction. Therefore, the magnetic field the material produces will depend on a balance between the two types. If there are more atoms aligned the other way, it will be where it will create the magnetic field.

External forces significantly influence the magnetic properties of the materials. Thus ferrimagnetic materials must develop logic circuits or data storage that are incredibly faster and store more data.

That is the basic principle that should happen. But, unfortunately, there is no reliable and quick way to switch the atoms’ orientation concerning storage devices.

The method of switching the polarity of a ferrimagnet is what researchers, including the researchers at MIT, are developing. And the MIT researchers found out that applying a small voltage is the most viable method. Their discovery could open the door to a new period of ferrimagnetic logic and devices for data storage.

The research, which appears in the journal Nature Nanotechnology is a collaborative project by professors and researchers at MIT and in South Korea, Spain, Germany, and Minnesota.

New system and new material

The new system uses gadolinium cobalt, which is used as an MRI agent. The researchers use a film made from gadolinium cobalt, an alloy belonging to a class of materials known as ferrimagnets, which are pretty rare.

The film is unique, with the two elements forming interlocking lattices of two different atoms. The gadolinium atoms lined up in one direction, and the cobalt atoms faced the opposite direction. This is because the overall magnetization of the material depends on the balance of atoms.

So, there is still the balance issue. But the researchers discovered another thing. They use the voltage to split water molecules along the film’s surface, separating oxygen from hydrogen. They removed the oxygen and the nuclei of the hydrogen atoms (protons), which they found, can penetrate through the film, and in so doing, alter the balance of the magnetic orientation, switching the direction of the magnetic field by 180 degrees. The loading of hydrogen reduces the magnetic moment of gadolinium substantially. According to one of the authors of the study, the magnetic moment is the measure of the field’s strength produced by the spin axis alignment of the atom.

Furthermore, the researchers found that changing the voltage instead of applying electrical current does not cause heating. Rather, it prevents waste energy via heat dispersion, making the process energy efficient.

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Stable process

The researchers say that the process can fail if they use other materials. They proved the stability of the gadolinium cobalt film by having the material undergo rigorous testing to see if it will have structural fatigue. The researchers found that there was no deterioration even if the material passed through 10,000 polarity reversals.

The film even has several properties. It acts like a spring and pulls back individual atoms that go out of alignment. Additionally, the spring-connected objects are inclined to generate waves the researchers call spin waves, which move through the material. Finally, the material’s magnetization causes it to vibrate at high frequencies. The oscillation is over the terahertz range.

This method creates an entirely new field, with various applications available in a few years. Of course, the most straightforward application will be sensors, but more complex applications can be seen in data and logic circuits.