Physicists Are Startled by This Magnetic Material That 'Freezes' When Heated

Something interesting happens when magnetic materials are cooled. The spins of their atoms freeze and lock into place in a static pattern.

Physicists have never seen the opposite before. All our expectations were turned upside down when the magnetic neodymium element froze.

Alexander Khajetoorians of the University of the Netherlands said that the magnetic behavior in neodymium was different from what they normally see.

It's like water becoming an ice cube when it's heated up.

The north and south magnetic poles are oriented the same way in three-dimensional space in a conventional ferromagnetic material.

The spins in some materials are random. The state is called a spin glass.

It has to be mixed with iron in order for it to make good magnets. It was only two years ago that physicists discovered that pure neodymium is a self-generated spin glass.

It seems that neodymium isn't the same as we thought.

The rise in temperature causes the energy in the material to increase. The motion of the spins is increased by this. The spins slow when you cool down a magnets.

The spin glass behaves more like a ferromagnet at freezing temperature.

A group of scientists wanted to investigate how neodymium behaves under different temperatures. When cooling a spin glass, the freeze state usually seen when cooling a spin glass is caused by the temperature of neodymium being raised.

The spins fell into disarray when the scientists cooled them down.

It's not clear why this happens since it's very rare that a natural material behaves in a different way than other materials. The scientists think it might have to do with frustration.

When a material is unable to attain an ordered state, it results in a disorderly ground state.

The researchers said that it is possible that neodymium has correlations in its spin glass state. Raising the temperature causes these to be weakened and also causes them to be frustrated.

The mechanism behind this odd behavior in which order emerges from disorder with the addition of energy could be revealed by further investigation.

"Magnetic material doesn't usually freeze the pattern in it's own way."

This could be applied to the behavior of a wide range of other materials.

Nature physics has published the research.