Question

Write two characteristics of a material to constructes a permanent magnet. Give two examples of such materials.

Answer 1

The material used for making a permanent magnet should possess high value of coercivity and also a resonable value of the retentivity. Moreover, the area of hysteresis curve should also be large. A permanent magnet is never taken through a complete cycle of magnetisation and hence the large area of hysteresis curve will not be a demerit of such a material. Steel and alnico fulfil all these requirements.