I work in the Aggregate industry and we use ceramic magnets to pull ferrous materials out of the feed of Aggregate materials passing by on a conveyor belt. So i have a basic knowledge about how they work, but my technical knowlege about magents is extremely lacking. Wondering if anyone would have any theories as to why a ceramic permanent magnet would lose its strength working in a place with extremely cold temparatures? I.E. -40° C. I know that permanent magnets become stronger when they are put in extremely cold temps, but i'm wondering if going from -40 to +20 every 24 hours for months in a row might gradually decrease the strength over time?? Any thoughts would be helpful. Thanx in advance.