Room-temperature quantum magnets flip states trillions of times per second as the terahertz realm approaches

 By University of Tokyo 

January 19, 2023

                            MRAM, a family of nonvolatile memory systems based on quantum magnetic materials, has the potential to outperform existing state-of-the-art memory technologies a thousand-fold. Antiferromagnets are substances that have had their ability to hold persistent memory states shown before, but they were challenging to read from. This new work, which has been published in Nature, lays the path for reading memory states effectively and perhaps very fast.

You can probably blink four times each second on average. You may argue that this blinking frequency is 4 hertz (cycles per second). It would be physically impossible for a human to blink at 1 gigahertz, or 1 billion times per second. However, this is the current order of magnitude at which modern high-end digital systems, such magnetic memory, change their states in response to operations. And many individuals want to push the limit 1,000 times farther, into the realm of terahertz, or a trillion times a second.

The materials utilised could act as a barrier to the development of quicker memory devices. Current high-speed MRAM chips employ ordinary magnetic, or ferromagnetic, materials but are not yet widely available to be found in your home computer. Tunneling magnetoresistance is a method used to read these. For this, the magnetic components of the ferromagnetic material must be arranged in parallel lines. The powerful magnetic field produced by this configuration, however, restricts how quickly data can be read from or written to the memory.

Antiferromagnets, a distinct form of material, are used in experiments that address this constraint, according to Professor Satoru Nakaji from the University of Tokyo's Department of Engineering.

"The ability to organise antiferromagnets in configurations other than parallel lines is one of the numerous ways that they vary from conventional magnets. This implies that we can rule out the magnetic field that parallel configurations would produce. It is believed that ferromagnets must be magnetised in order for tunnelling magnetoresistance to read from memory. Surprisingly, however, we discovered that a particular family of antiferromagnets may exist without magnetization and, perhaps, function at extremely high speeds."

At room temperature, switching rates in the terahertz region, according to Nakatsuji and his colleagues, are feasible, whereas earlier experiments necessitated considerably cooler temperatures and did not provide such encouraging findings. The team must, however, enhance how it makes its gadgets if it wants to improve upon its original concept.

According to researcher Xianzhe Chen, "the atomic ingredients of our materials—manganese, magnesium, tin, oxygen, and so on—are somewhat common, but the technique in which we mix them to generate a usable memory component is fresh and unexpected."

"We use two procedures known as molecular beam epitaxy and magnetron sputtering to create crystals in a vacuum, in very thin layers. The purer the samples we can develop, the greater the vacuum. It's a very difficult process, and if we can make it easier, we'll generate products that are both more efficient and easier to live with."

These antiferromagnetic memory systems make use of entanglement, often known as interaction at a distance, a quintessential phenomena. However, despite this, there is no clear connection between this discovery and the increasingly well-known topic of quantum computing. However, academics contend that advancements like these could be beneficial or even necessary to create a link between the established subject of electrical computing and the new discipline of quantum computing.

Under the terms of a Creative Commons licence, this article has been taken from PHYSOORG. Go here to read the original article.