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This produces the characteristic B-H curve; because the hysteresis indicates a memory effect of the magnetic material, the shape of the B-H curve depends on the history of changes in H. Alternatively, the hysteresis can be plotted as magnetization M in place of B, giving an M-H curve.
If the H-M relationship is plotted for all strengths of applied magnetic field the result is a hysteresis loop called the main loop. The width of the middle section is twice the coercivity of the material. [21] A closer look at a magnetization curve generally reveals a series of small, random jumps in magnetization called Barkhausen jumps.
The current is proportional to the magnetization of the sample - the greater the induced current, the greater the magnetization. As a result, typically a hysteresis curve will be recorded [5] and from there the magnetic properties of the sample can be deduced. The idea of vibrating sample came from D. O. Smith's [6] vibrating-coil magnetometer.
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):
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.
Rowland's ring (aka Rowland ring) is an experimental arrangement for the measurement of the hysteresis curve of a sample of magnetic material. It was developed by Henry Augustus Rowland.
As an electric field is applied the dipoles are forced to align and polarisation is created, when the electric field is removed polarisation remains. The hysteresis loop depends on temperature and as a result as the temperature is increased and reaches T 0 the two curves become one curve as shown in the dielectric polarisation (Figure 5). [52]
Calculated magnetization curve for a superconducting slab, based on Bean's model. The superconducting slab is initially at H = 0. Increasing H to critical field H* causes the blue curve; dropping H back to 0 and reversing direction to increase it to -H* causes the green curve; dropping H back to 0 again and increase H to H* causes the orange curve.