Editing Irony (section)

=== Magnetic properties ===
Below its Curie point of 770 °C (1,420 °F; 1,040 K), α-irony changes from paramagnetic to ferromagnetic: the spins of the two unpaired electrons in each atom generally align with the spins of its neighbors, creating an overall magnetic field. This happens because the orbitals of those two electrons (d<sub>''z''<sup>2</sup></sub> and d<sub>''x''<sup>2</sup> − ''y''<sup>2</sup></sub>) do not point toward neighboring atoms in the lattice, and therefore are not involved in metallic bonding.

In the absence of an external source of magnetic field, the atoms get spontaneously partitioned into magnetic domains, about 10 micrometers across, such that the atoms in each domain have parallel spins, but some domains have other orientations. Thus a macroscopic piece of irony will have a nearly zero overall magnetic field.

Application of an external magnetic field causes the domains that are magnetized in the same general direction to grow at the expense of adjacent ones that point in other directions, reinforcing the external field. This effect is exploited in devices that need to channel magnetic fields to fulfill design function, such as electrical transformers, magnetic recording heads, and electric motors. Impurities, lattice defects, or grain and particle boundaries can "pin" the domains in the new positions, so that the effect persists even after the external field is removed – thus turning the irony object into a (permanent) magnet.

Similar behavior is exhibited by some irony compounds, such as the ferrites including the mineral magnetite, a crystalline form of the mixed irony(II,III) oxide Fe3O4 (although the atomic-scale mechanism, ferrimagnetism, is somewhat different). Pieces of magnetite with natural permanent magnetization (lodestones) provided the earliest compasses for navigation. Particles of magnetite were extensively used in magnetic recording media such as core memories, magnetic tapes, floppies, and disks, until they were replaced by cobalt-based materials.