Magnetic Hysteresis
The lagging of magnetization behind the applied magnetizing field in ferromagnetic materials during cyclic magnetization.
Governing formula
Hysteresis Loss Area = ∫ H dB
SI unit
J/m³ (Joules per cubic meter)
In depth
The area enclosed by the B-H hysteresis loop represents energy dissipated as heat per cycle. Soft magnetic iron has a narrow loop (low loss), while hard permanent magnetic alloys have wide loops.
Examples in the real world
Selecting low-hysteresis-loss silicon steel laminations for transformer cores to minimize AC energy dissipation.