Some ways to deal with overheating of mobile phones

Today's life is inseparable from mobile phones, what should we do if our mobile phones get hot? Modern computer memory encodes information by switching magnetic bits within the device. Now, in a groundbreaking study, researchers from the Department of Electrical and Computer Engineering at the National University of Singapore have discovered a new and efficient way to use "spin waves" to switch magnetization at room temperature, allowing for more energy-efficient autonomous processes. Spin memory and logic devices.

Conventional electronic chips suffer from large amounts of "Joule heating," which occurs due to the flow of electrical current that generates high temperatures. This is caused by rapid motion and frequent collisions between moving charges inside the device. This serious problem not only results in massive power consumption, but also affects the chip's processing speed and limits the number of chips that can be integrated into a device.

"We often encounter such problems and inconveniences when using phones, computers and other electronic devices. We often find that these devices become 'hot' and 'slow' and, moreover, we need to charge them frequently and have to bring another A portable charger sometimes," explains Professor Yang Hyunsoo, leader of the research team. Therefore, instead of adopting the standard electron injection method used in traditional electronics, Professor Yang's team creatively used "spin waves" to switch the magnetization intensity. Spin waves are propagating disturbances in the order of magnetic materials. From a quasi-particle perspective, spin waves are called "magnons."

The team constructed a two-layer system consisting of an antiferromagnetic magnon transport channel and a topological insulator spin source. In a world first, they then successfully demonstrated spin wave-driven magnetization switching in adjacent ferromagnetic layers at room temperature with high efficiency. New switching scheme based on spin waves avoids charge movement. Therefore, the Joule heating and power consumption of the device will be greatly reduced. Advances in spin wave-based switching technology could open up a new path to energy-saving chips.

The findings were published in the journal Science on November 29, 2019.

Spin waves and magnetic torque

Dr. Wang Yi, first author of the work, explains: "Even in insulators, spin waves (magnons) can convey spin information without involving moving charges. Compared with electron spins, this unique The properties may allow for longer spin propagation but are less dissipative."

"If we transfer the spin information from the magnon to the local magnetization, then we can control the magnetization, which can be understood as 'magnetic torque,'" said Dr. Wang. Just like a linear force is a push or a pull, torque is also It can be thought of as a distortion of the object. "As a result, this new method of manipulating magnetization could be used in future data memories and logic devices," he added.

Potential applications and next steps

"Our work is the first to show that Manon torque is sufficient to switch magnetization at room temperature. Even the efficiency of Manon torque is comparable to previously pursued electrospin torque efficiencies. We believe that this can be further improved by engineering devices It, and thus the magnetic torque will be more energy-saving." Professor Yang said.

"We know that electrical spin torque has opened the era for spintronic device applications such as magnetic random access memory (MRAM). We believe that reports of new magneto-torque schemes for magnetization switching are important in spin A game-changer in electronics. “Not only the new research field of Magnics was revitalized, but also the practical devices that Magnicians operated. " Dr. Wang said.

Next, the research team will further design the efficiency of the magnetic torque and explore all magnetic devices that do not involve electrical components. In addition, the operating frequency of spin waves is in the terahertz range. Terahertz devices can transmit data at much higher speeds than currently available. Professor Yang said: "Therefore, devices based on Magno torque will allow ultra-high-speed applications in the future." The above are some simple solutions to mobile phone heating, I believe they will be helpful to everyone.