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The downward curve after saturation, along with the lower return curve, form the main loop. The intercepts h c and m rs are the coercivity and saturation remanence. Magnetic hysteresis occurs when an external magnetic field is applied to a ferromagnet such as iron and the atomic dipoles align themselves with it.
This is one of the most popular models of magnetic hysteresis. Its main advantage is the fact that this model enables connection with physical parameters of the magnetic material. [2] Jiles–Atherton model enables calculation of minor and major hysteresis loops. [1] The original Jiles–Atherton model is suitable only for isotropic materials. [1]
Saturation is most clearly seen in the magnetization curve (also called BH curve or hysteresis curve) of a substance, as a bending to the right of the curve (see graph at right). As the H field increases, the B field approaches a maximum value asymptotically , the saturation level for the substance.
The curves form a hysteresis loop. Hysteresis is the dependence of the state of a system on its history. For example, a magnet may have more than one possible magnetic moment in a given magnetic field, depending on how the field changed in the past. Plots of a single component of the moment often form a loop or hysteresis curve, where there are ...
In an ordinary magnetic hysteresis measurement, h starts at a large positive value and is decreased to a large negative value. The magnetization direction starts on the blue curve. At h = 0.5 the red curve appears, but for h > 0 the blue state has a lower energy because it is closer to the direction of the magnetic field. When the field becomes ...
The energy loss, called core loss, is due mainly to two effects: magnetic hysteresis and, in conductive materials, eddy currents, which consume energy from the source of the magnetic field, dissipating it as waste heat in the magnetic material. The equation is used mainly to calculate core losses in ferromagnetic magnetic cores used in electric ...
The maximum energy product is defined based on the magnetic hysteresis saturation loop (B-H curve), in the demagnetizing portion where the B and H fields are in opposition. It is defined as the maximal value of the product of B and H along this curve (actually, the maximum of the negative of the product, −BH, since they have opposing signs):
This means that the capillary pressure for a drainage process is different from the capillary pressure of an imbibition process with the same fluid phases. Hysteresis does not change the shape of the governing flow equation, but it increases (usually doubles) the number of constitutive equations for properties involved in the hysteresis.