Ferromagnetism depends on the arrangement of orbitals and spin in the valence electrons of an atom (below its Curie point). But what is so special about the orbitals of iron, nickel and cobalt, to make them the main ferromagnetic materials, and everything else more or less pale in comparison?
Please note that I am not asking "how do magnets work?". I know about domains, EM and the like, but on a strictly atomic/QM level, I would like to understand what sets these materials so greatly apart from dozens of others with seemingly similar orbital arrangements.
