When heating the magnetic element neodymium to the appropriate temperature, an interesting phenomenon occurs, reversing all logic.
Previously, if we cooled magnetic materials to the right temperature, the spins of the atoms would be “frozen” and locked into a static pattern.
A neodymium magnet toy. (Photo: Wikipedia).
However, physicists have now accidentally discovered the opposite when they heated a sample of natural magnetic element neodymium.
“The behavior of the magnets in neodymium that we observed is actually the opposite of what normally happens“, said Alexander Khajetoorians, a physicist at Radboud University (Netherlands). “This is quite surreal, like liquid water turning into a solid block of ice when heated.”
This occurs in some materials, such as alloys of copper and iron, where the spins of the atoms are arranged quite randomly. This state is known as spin glass.
To test this, physicist Benjamin Verlhac at Radboud University and a team of scientists raised the temperature of neodymium from -268 degrees Celsius to -265 degrees Celsius. As a result, the frozen state actually occurred, resembling what happens when cooling another spin glass system.
Notably, when the scientists attempted to cool neodymium back down, the atomic spins once again fell into a state of chaos.
The strange phenomenon occurring when heating neodymium material, similar to “freezing” other magnetic materials.
The reason why this occurs remains unclear, as it is very rare for a natural material to behave in a manner completely opposite to all other materials of its kind.
Scientists believe this may be related to a physical phenomenon known as “Geometrical Frustration,” which refers to atoms tending to adhere to unusual positions. This often occurs when the material cannot achieve an ordered pattern, leading to a disordered ground state.
Researchers also speculate that neodymium may have certain correlations in its states that depend on temperature. Accordingly, increasing or decreasing the temperature could weaken the bonds, causing the aforementioned disorder phenomenon.
The researchers note that this has implications beyond physics, as it could help humanity uncover new orders behind each material. “If we can model how these materials operate, we may extrapolate behaviors for many other types of materials,” explains physicist Alexander Khajetoorians.
