Dependence of a system's observed state on the path by which its control parameters were reached. In a first-order phase transition, a metastable local minimum may persist after another phase becomes globally stable, so increasing and decreasing the control parameter give different switching points. Nucleation and sweep rate determine actual switching; a mean-field spinodal point is a local-stability limit, not the equilibrium phase coexistence condition.
Magnetic hysteresis means that a material's magnetization depends on its field history as well as the present applied field. A closed quasistatic magnetic cycle dissipates energy per unit volume equal to its – loop area. It is relevant to remanence in permanent magnets and core losses in electrical transformers.
Magnetic coercivity is the magnitude of a reverse applied magnetic field intensity required to bring a previously magnetized specimen's magnetization to zero on a specified hysteresis branch. It depends on material, preparation and measurement history. It differs from remanent magnetization, which is the remaining magnetization at zero applied field.
The magnitude of reverse magnetic field strength at which a previously magnetized specimen's magnetic flux density vanishes on a specified magnetic hysteresis branch. Intrinsic magnetic coercivity instead refers to zero magnetization. Because , their zero conditions generally occur at different applied fields. The preparation, branch and specimen geometry must be specified when comparing measurements.
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Hysteresis is a phenomenon where the response of a system depends on its past states. It is commonly observed in various fields such as physics, engineering, and economics. In simple terms, hysteresis describes a situation where the effect of a certain influence (like force, temperature, or magnetism) on a system depends not only on the current value of that influence but also on the history of how that influence has changed over time.