How do magnetic waves behave and propagate in antiferromagnets? What role do “domain walls” play in the process? And what can all this mean for the future of data storage? These issues are addressed in a recent study in the journal Physical Review Letters by an international research team led by Dr. Davide Bossini, a constant physicist. The research team reports on the magnetic phenomena of antiferromagnets, which can be generated by ultrafast (femtosecond) laser pulses and which can potentially add new functions to materials for energy-efficient and ultrafast data storage applications.
Big data technologies and the wildly growing use of cloud-based data services means that the global demand for data storage is constantly increasing along with the demand for ever faster data processing. However, currently available technologies will not be able to keep up forever. “It is estimated that the growing demand can only be met for a limited period of time, around 10 years, if new, more efficient data storage and processing technologies cannot be developed by then,” Bossini was quoted as saying by ScienceDaily.
it is enough to simply build more and more data centers with current efficiency. The technologies of the future need to be faster and more energy efficient than mass storage based on traditional magnetic hard disks. One class of materials, antiferromagnets, are promising candidates for the development of the next generation of information technology.
We are all familiar with household magnets made of iron or other ferromagnetic materials. In these materials, the atoms are all magnetically oriented in the same direction as the compass pointers, resulting in magnetic polarization (magnetization) that affects the environment. Antiferromagnets, on the other hand, have atoms whose alternating magnetic moments extinguish each other. Thus, antiferromagnets do not have a net magnetization and therefore have no magnetic effect on the environment.
Inside, however, these naturally occurring antiferromagnetic bodies are divided into many smaller areas, called domains, where opposite magnetic moments are directed in different directions. . Domains are separated by transitional areas called ‘domain walls’. “Although these transition areas are well known in antiferromagnets, little has been known so far about the effect of domain walls on the magnetic properties of antiferromagnets, especially at extremely short time intervals,” says Bossini.
In the current study, researchers describe what happens when antiferromagnets (more specifically, nickel oxide crystals) are exposed to ultrafast (femtosecond) laser pulses. The femtosecond scale is so short that even light can only travel very short distances during this time. In a fraction of a quadrillionth of a second (a femtosecond), light is only 0.3 micrometers, which is the diameter of a small bacterium.
The international research team has shown that domain walls play an active role in antiferromagnetic in the dynamic properties of nickel oxide. Experiments have shown that magnetic waves of different frequencies can be induced, amplified, and even interconnected through different domains, but only in the presence of domain walls. “Our observations show that the ubiquitous domain walls in antiferromagnets can potentially be used to impart new functions to these materials on an ultrafast scale,” says Bossini.
The ability to pair different magnetic waves through domain walls highlights the magnetic the possibility of active control of the spatial and temporal propagation of waves and of the energy transfer between individual waves on a femtosecond scale. This is a prerequisite for the use of these materials for the ultra-fast storage and processing of data.
Such anti-ferromagnetic data storage technologies would be several orders of magnitude faster and more energy efficient than at present. They would also be able to store and process larger amounts of data. Because materials do not have net magnetization, they would be less susceptible to failure and external manipulation. “Future technologies based on antiferromagnets would thus meet all the requirements of the next generation of data storage technology. They also have the opportunity to keep pace with the growing demands for data storage and processing capacity,” Bossini summed up the potential of the new technology
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