magnetism and magnetic materials.

1. Which Material are Good for Magnetization?
MUHMMAD USAMA DAUD
M.PHIL (PHYSICS) SCHOLOR

2. Magnetization
An electron revolving in an orbit around the nucleus of an atom is equivalent
to a tiny current loop, which gives rise to a magnetic field. Also, the magnetic
field is associated with the angular momentum of the electron’s spin on its
own axis.

3. Classification of Magnet
 Ferromagnetic
 Paramagnetic
 Diamagnetic

4. Ferromagnetic
 A type of material that is highly attracted to magnets and can
become permanently magnetized is called as ferromagnetic.
 The relative permeability is much greater than unity and are
dependent on the field strength.
 These have high susceptibility.

5. Paramagnetic
 It is a substance or body which very weakly attracted by the
poles of a magnet, but not retaining any permanent magnetism.
 These have relative permeability slightly greater than unity and
are magnetized slightly.
 They attract the lines of forces weakly.

6. Diamagnetic
 It is a substance which create a magnetic field in opposite to an
externally applied field.
 Susceptibility is negative.
 These have relative permeability slightly less than unity.
 . They repel the lines of force slightly.

7. Comparison of these types

9. Material Good for Magnetization
Among the Ferromagnetic ,Paramagnetic and Diamagnetic ,
Ferromagnetic is good for magnetization.

10. More about Ferromagnetic Materiel
 Ferromagnetic materials are those which exhibit strong magnetic
properties when placed in a similar direction of the field. At first, we shall
know the concept of domain. It is generally a small locale in these
materials that has a particular spin alignment because of quantum
mechanical exertion. The permeability nature of these materials is
extremely high, and it ranges almost several thousand. The reverse
magnetic effects of the electron spin and orbital motion will not get
eliminated in these materials. There exists a correspondingly substantial
contribution from every atom that helps in the development of the internal
magnetic field. Due to this internal magnetic field, the property of the
magnetic field will be increased.

11. Magnetization of Ferromagnetic
Materiel
 In Ferromagnetic there exist a Small region called Domain.
 The domains are of microscopic size of the order of millimeter or less but
large enough to contain 1012 to1016 atoms.
 Each domain behaves as a small magnet with its own north and south
pole. In unmagnetized Iron the domain are oriented in disorderly fashion.
 When the specimen is placed in an external magnetic field the domain
lines up parallel to the lines of external magnetic field and the entire
specimen becomes saturated and make a powerful magnet.

12. Concept of Hysteresis in
Ferromagnetic Materials
 When there is the removal of an external magnetic field, these
materials will not get demagnetized to the whole. So as to let them
lose complete magnetism, the reverse magnetic field has to be
applied in the opposite direction. So, this procedure of
ferromagnetic materials holding magnetization even the removal of
the external field is termed hysteresis. And the material
magnetization evaluated in magnetic flux density (B) v/s applied
external magnetic field (H) will result in a loop and this is termed as
a hysteresis loop. The figure clearly depicts this procedure.

13. Hard and soft magnetic material
Magnetically Hard Material :
 High retentivity.
 High coercivity.
 Strong magnetic reluctance.
 Hysteresis loop is more rectangular in shape.
Examples :
cobalt steel, chromium steel, etc.

14. Magnetically Soft Material
 The magnetic energy stored is not high.
 They have low remanence.
 Hysteresis loop is narrow.
Example
Pure iron, carbon steel ,& nickel steel, etc.

15. Applications
 Used for non-volatile data storage in hard drives, tapes and in many
others.
 Employed in information processing because of the collaboration of
electric light and power with magnetic influence.
 Utilized in the equipment like microphones, and capacitor.
 Used in devices such as generators, telephone, loudspeakers, electric
motors and magnetic strips at the backside of debit and credit cards.

16. Question?

17. Thanks for patience.