SOLUTION

• If the domain walls are easy to move, the coercive field is low, it is easy to magnetize the material, Such a material is called a soft magnetic material.
• If it is difficult to move the domain walls, the coercive field is large and the material is magnetically hard.

Fig.shows the nature of hysteresis loop of hard magnetic material (steel).The Hard magnetic material has a wider hysteresis loop as shown in the figure below and results in a large amount of energy dissipation and the demagnetization process is more difficult to achieve.

Property of Hard Magnet Material

• Hard magnetic materials have large hysteresis loss due to larger hysteresis loop area.
• in these materials, the domain wall movement is difficult because of the presence of impurities and crystal imperfections and it is irreversible in nature.
• The coercivity and retentivity are large. Hence, these materials cannot be easily magnetized and demagnetizer
• Hard magnetic materials are used to produce permanent magnet.
• Hard Magnetic Material has Low Susceptibility and Permeability.
• The hysteresis loop of hard mateirals is rectangular in shape.
• Magnetic Energy Stored is High.
• The eddy current losses are high.
• They are suitable for making permanent magnet e.g Alnico