Researchers observed a strange new behavior when a magnetic material was heated. When the temperature rises, the magnetic spin in this material “freezes” into a static mode, which usually occurs when the temperature drops. The researchers published their findings in the journal Nature Physics.
Researchers found this phenomenon in neodymium materials. A few years ago, they described this element as “self induced spin glass”. Spin glass is usually a metal alloy, for example, iron atoms are randomly mixed into a grid of copper atoms. Each iron atom is like a small magnet, or spin. These randomly placed spins point in various directions.
Unlike traditional spin glasses, which are randomly mixed with magnetic materials, neodymium is an element. In the absence of any other substance, it shows the behavior of vitrification in crystal form. Rotation forms a pattern of rotation like a spiral, which is random and constantly changing.
In this new study, researchers found that when they heated neodymium from -268 ° C to -265 ° C, its spin “frozen” into a solid pattern, forming a magnet at a higher temperature. As the material cools, the randomly rotating spiral pattern returns.
“This mode of ‘freezing’ usually does not occur in magnetic materials,” said Alexander khajetoorians, a scanning probe microscope professor at Radboud University in the Netherlands.
Higher temperatures increase energy in solids, liquids, or gases. The same applies to magnets: at higher temperatures, rotation usually begins to wobble.
Khajetoorians said, “the magnetic behavior of neodymium we observed is actually contrary to what happens’ normally ‘.” “This is quite counter intuitive, just like water turns into ice when heated.”
This counterintuitive phenomenon is not common in nature – few materials are known to behave in the wrong way. Another well-known example is Rochelle salt: its charges form an ordered pattern at higher temperatures, but are randomly distributed at lower temperatures.
The complex theoretical description of spin glass is the theme of the 2021 Nobel Prize in physics. Understanding how these spin glasses work is also important for other areas of science.
Khajetoorians said, “if we can finally simulate the behavior of these materials, it can also infer the behavior of a large number of other materials.”
Potential eccentric behavior is related to the concept of degeneracy: many different states have the same energy, and the system becomes frustrated. Temperature can change this situation: only a specific state exists, allowing the system to explicitly enter a mode.
This strange behavior may be used in new information storage or computing concepts, such as brain like computing.
Post time: Aug-05-2022
