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Scientists unveil new way to control magnetism in super-thin materials

A powerful new method to control magnetic behavior in ultra-thin materials could lead to faster, smaller and more energy-efficient technologies, a study suggests.

Researchers have developed a new way to precisely tune magnetism using a material—called CrPS₄—that is just a few atoms thick. The study is in the journal Nature Materials.

The advance could solve a long-standing scientific problem and pave the way for the development of new smart magnetic technologies, from computer memory devices to next-generation electronics, the team says.

Magnetism is central to how digital memory works, with tiny magnetic regions inside computers used to store information.

These magnetic regions are controlled by tiny shifts in the magnetic behavior, a process called exchange bias. However, until now, exchange bias was difficult to study and even harder to control because it happens at buried, imperfect interfaces between different materials.

Researchers from the University of Edinburgh, Boston College and Binghamton University have devised a way of overcoming these challenges.

Instead of stacking different materials on top of each other, the team discovered they could achieve the same control within CrPS₄, a type of semiconductor.

In ultra-thin flakes of CrPS₄, layers of atoms naturally form regions with different magnetic properties due to its thickness. Using cutting-edge imaging techniques and large-scale simulations, researchers were able to see how magnetic regions formed, interacted and shifted at the boundaries between different numbers of layers.

The imaging technique—known as nitrogen-vacancy (NV) center magnetometry—works like an ultra-sensitive magnetic microscope, using diamond sensors to visualize tiny magnetic fields.

By changing the arrangement of layers within CrPS₄, the researchers found they could turn the exchange bias on or off, like flipping a switch. The process is controllable and reversible, something that could be very useful for future technologies, the team says.

Dr. Elton Santos, from the University of Edinburgh's School of Â鶹ÒùÔºics and Astronomy, said, "The regions inside CrPS₄ line up side by side like lanes on a highway. The border between them forms a perfect interface, allowing us to study and control magnetic behavior with incredible precision."

Not only does the discovery deepen scientists' understanding of magnetism, it also lays the groundwork for building smarter, smaller and more reliable magnetic devices, the team says.

It could help engineers design ultra-compact memory chips, reconfigurable sensors or even quantum computing devices based on magnetic principles. CrPS₄ is stable in air and easy to work with, making it an ideal candidate for real-world applications, not just lab experiments, they add.

Dr. Santos continues, "This breakthrough opens a window into the invisible world of atomic-scale magnetism. This work gives us a transparent and reliable platform to understand and engineer magnetism at the atomic scale. It opens the door to a whole new class of magnetic technologies."