The first quadrant shows the behaviour of the material when it is being magnetised. When an external magnetic field of strength H is applied, the magnetic moments are oriented parallel to this field. When all magnetic moments are oriented, the magnetisation is said tob e saturated.
The second quadrant of the hysteresis loop is demagnetisation curve. The shape of the demagnetisation curve and ist initial and final points, giving remanence Br and coercivity HC , represent the most important magnetic properties of a permanent magnet. All curves in the figures of this brochure show average values of quantities. The B and J curves in the third and fourth quadrant are the same as in the first two quadrants, reflected throught the origin. Here the magnetisation is rotated by 180 °C (in the opposite direction).