Caused by movement of electrons, where each electron may contain two electrons with opposite spins (spin quantum number)
- Each spinning electon produces a magnetic field, whose bohr magnetic moment can be cancelled by adding an electron in the same orbital spinning in the opposite direction
- - FerrImagnetriic ions have partially filled 3d electrion shells containing several unpaired elctrons. E.g MAGNETITE which has a net four electrons spinnig in one direction in the 3d electron orbital
- BREF - Atoms ions in adjacent structural sites have antiparallel magnetic moments because of Exchange coupling.