Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: matthewh on 03/06/2019 10:30:45

Title: Do magnets naturally weaken over time?
Post by: matthewh on 03/06/2019 10:30:45

Rob wants to know:

I’ve been wondering - do magnets weaken over time?

Let's see what you have as a response!

Title: Re: Do magnets naturally weaken over time?
Post by: evan_au on 03/06/2019 11:33:33

Yes.

In "Soft" magnetic materials, the magnetic domains are very mobile. They line up when an external magnetic field is applied, and migrate back to equal and opposite North/South domains as soon as the external magnetic field is removed.

"Hard" magnetic materials retain their magnetic field after the external field is removed. But they do decay over time - and faster with higher temperatures or vibration. When the temperature exceeds the Curie temperature, the magnetism is lost entirely.

See: https://en.wikipedia.org/wiki/Magnet#Demagnetizing_ferromagnets