What are the most significant properties of permanent magnetic materials? Explain.

Ans:

The most significant properties of permanent magnetic materials are

(i) Remanence (Residual magnetism (Br) :

 It  is  the  intensity  of  the  residual  magnetism  after  magnetism  field(H)  has  been removed.

(ii) Coercive force (Hc):

It is the resistance of magnetic material to demagnetization by electromagnetic techniques.

(iii) Energy product value (BH) _max:

It is a measure of the amount of magnetic energy stored a magnet after magnetising field is removed.

Requirement of permanent magnetic material is that product of B and H should be maximum possible and it takes place when product of CD and DE on demagnetising curve is at a maximum. Depending upon requirement of remanence and coercive force, permanent magnetic material is selected.