Data storage

Discovery of magnetic phenomena paves the way for faster and more efficient data storage


How do magnetic waves behave in antiferromagnetics and how are they propagated? What role do “domain walls” play in the process? And what could that mean for the future of data storage? These questions are the subject of a recent publication in the journal Physical examination letters of an international research team led by the physicist of Constance Dr. Davide Bossini. The team reports magnetic phenomena in antiferromagnetics that can be induced by ultra-fast (femtosecond) laser pulses and with the potential to endow materials with new functionalities for ultra-fast and energy-efficient data storage applications.

Demand for storage capacity is growing faster than available infrastructure

The growing use of big data technologies and cloud-based data services means that the global demand for data storage is steadily increasing, along with the need for ever faster data processing. At the same time, the technologies currently available will not be able to keep up indefinitely. “Estimates indicate that increasing demand can only be met for a limited period of around 10 years, if no new, more efficient technology for storing and processing data can be developed in the meantime,” the physicist says. Dr Davide Bossini of the University of Constance and lead author of the study.

Faster and more efficient data storage

A research team involving the University of Constance is discovering magnetic phenomena in antiferromagnetics that could pave the way for the development of faster and more efficient data storage. Credit: University of Constance

To prevent a data crisis from occurring, it will not be enough to simply continue to build more and more data centers, operating at the current state of the art. The technologies of the future must also be faster and more energy efficient than traditional mass data storage, based on magnetic hard disks. One class of materials, antiferromagnetics, is a promising candidate for the development of the next generation of information technology.

The structure of antiferromagnetics

We are all familiar with household magnets made from iron or other ferromagnetic materials. These materials have atoms that are all magnetically oriented in the same direction – like the small needles of a compass – so that magnetic polarization (magnetization) occurs which affects the surrounding environment. Antiferromagnetics, on the other hand, have atoms with alternating magnetic moments that cancel out. The antiferromagnets therefore have no net magnetization and therefore no magnetic impact on the surrounding environment.

Inside, however, these antiferromagnetic bodies that are found in abundance in nature are divided into many smaller areas called domains, where oppositely oriented magnetic moments are aligned in different directions. Domains are separated from each other by transition zones called “domain walls”. “Although these transition zones are well known in antiferromagnets, so far little has been known about the influence of domain walls on the magnetic properties of antiferromagnetics – especially during extremely short time increments,” explains Dr Bossini.

Femtosecond magnetic phenomena

In this article, the researchers describe what happens when antiferromagnetics (more precisely: nickel oxide crystals) are exposed to ultrafast (femtosecond) laser pulses. The femtosecond scale is so short that even light can only travel a very small distance during that period of time. In a quadrillionth of a second (a femtosecond), light travels barely 0.3 micrometers, the equivalent of the diameter of a small bacteria.

The international team of researchers has shown that domain walls play an active role in the dynamic properties of antiferromagnetic nickel oxide. The experiments revealed that magnetic waves of different frequencies could be induced, amplified and even coupled to each other in different domains, but only in the presence of domain walls. “Our observations show that the ubiquitous presence of domain walls in antiferromagnetics could potentially be used to endow these materials with new functionalities at the ultrafast scale,” explains Bossini.

Important steps towards more efficient data storage

The ability to couple different magnetic waves through the walls of the domain highlights the potential to actively control the propagation of magnetic waves in time and space as well as the transfer of energy between individual waves on the femtosecond scale. This is a prerequisite for using these materials for ultra-fast data storage and processing.

Such antiferromagnetic-based data storage technologies would be orders of magnitude faster and more energy efficient than current technologies. They would also be able to store and process a larger amount of data. Since the materials do not have a clear magnetization, they would also be less vulnerable to malfunctions and external manipulation. “Future technologies based on antiferromagnetics would thus meet all the requirements of the next generation of data storage technology. They also have the potential to keep pace with the growing demand for storage and data processing capacity, ”Bossini concludes.

Reference: “Ultrafast Amplification and Nonlinear Magnetoelastic Coupling of Coherent Magnon Modes in an Antiferromagnet” by D. Bossini, M. Pancaldi, L. Soumah, M. Basini, F. Mertens, M. Cinchetti, T. Satoh, O. Gomonay and S. Bonetti, August 9, 2021, Physical examination letters.
DOI: 10.1103 / PhysRevLett.127.077202

Highlights:

  • Study of the role of domain walls in the dynamic magnetic properties of antiferromagnetics at the ultrafast time scale
  • In the presence of domain walls and with the help of laser pulses, magnetic waves of different frequencies can be induced, amplified and coupled to each other in different domains of the nickel oxide material
  • The active control of the propagation of magnetic waves in time and space as well as the transfer of energy between individual waves in antiferromagnetics is a promising step towards the use of materials in future data storage and in data storage. data technologies.
  • Funding: German Research Foundation (DFG), European Cooperation in Science and Technology (COST), Knut and Alice Wallenberg Foundation, Swedish Research Council (VR), European Research Council (ERC) and National Science Foundation (NSF) ).