Note that there are three possible magnetic properties for a given alloy:
1. ferromagnetism is a very strong effect (high positive permeability), non-linear (variable permeability >> +1), that shows hysteresis, where electron spin magnifies the applied field
2. paramagnetism is a much weaker effect (low positive permeability, > +1, where vacuum = +1) that is close to linear without hysteresis, also due to electron spin
if you heat a ferromagnet above its Curie point (transition temperature), it becomes paramagnetic
3. diamagnetism is another weak effect (low negative permeability, < -1) found in materials such as copper, where the orbiting electrons resist the applied field[/li][/list]