I'm trying to understand the direction of magnetic moments in a ferromagnetic material after cooling down below it's Curie temperature.
A permanent magnet of ferromagnetic material will loose it's order and become paramagnetic above the it's Curie temparature.
As far as I understand, all information about the direction of it's previous magnetisation is lost here - is that correct?
I understand that spontaneous magnetisation happens when cooling down.
What's unclear to me is what influences the direction of the spontaneous magnetisation:
- It could be random, depending on some initial cluster of parallel magnetic moments that gets dominant
- it could be determined by the external magnetic field - for example of the earth, if there is no stronger one.
- or does it somehow relate to the previous magnetisation? Maybe based on contminations with material of higher curie temperature?