In this Demonstration, is increased until the magnet becomes saturated, with all the domains aligned for a maximum induction . The iron bar will retain its magnetization indefinitely, even after the external field is removed. In order to demagnetize the bar, a magnetic field in the opposite direction must be applied. The iron resists demagnetization, with lagging behind changes in . When is reduced to zero, the flux density is reduced slightly to , known as the remanence. Only when the magnetic field is increased to a value in the opposite direction, known as the coercivity, does the iron lose its magnetization and do its domains return to random orientations. The area enclosed by one cycle on the vs. plot is equal to the energy dissipated as heat.

The parameters in this Demonstration are representative of many iron alloys (including steels). Other magnetic materials, including rare-earth elements such as neodymium, are capable of much higher magnetic fluxes. The slider that cycles the magnetic field represents possible physical behavior only when moved from left to right.