magnetism

Magnetisation Fundamentals

At first magnetism magnetic material like iron is characterize by the property that is constituent atoms may have individual magnetic moments.

Atomic Magnetisation

  • magnetism begins from atoms due to below explanation
  • Magnetic field is produce by orbit of electrons and spin of electrons
Atomic Magnetisation
Magnetisation Atomic Magnetisation
Atomic Magnetisation
Magnetisation Atomic
Atomic Magnetisation
Atomic Magnetisation

Magnetisation of Iron – magnetism

A magnetic material like iron is characterized by the property that is constituent atoms may have individual magnetic moments (i.e. individual atoms can act as very small magnetic dipoles).

This property of atoms can be attributed to the orbital motion of electrons as well as to their spin (i.e. rotation of electron around their own axis)

Also In an initially magnetised piece of iron, there magnetic dipoles are disoriented such that the total effect of magnetisation is zero. However, under an externally applied magnetising force(H) these magnetic dipoles gradually become oriented in the direction H.

No external field un-magnetised magnetism
No external field un-magnetised
with external field magnetised magnetism
with external field magnetised

The orientation of magnetic dipoles in particular direction will cause the magnetic flux density (B) inside the material to increase by many times. This process is call Intrinsic Magnetization”. Therefore, we must introduce a new constant a relative permeability and then the external magnetizing field strength (H) and magnetic flux density (B) is reached by.

For the free space

B = µ0H                                               µ0 = Permeability for free space (No magnetic dipoles)

For magnetic materials

B = µ0H + Bi                                        Bi = Intrinsic magnetization

this Bi = Intrinsic magnetization

B = µ0H + µ0XmH                                

Xm =Magnetic susceptibility

B = µ0 (1 + Xm) H                 

B = µ0 µr H     

µr = Relative permeability                                     

B = µ H                                                 µ = µ0 µr

µ is permeability, ability of a material to support the formation of a magnetic field inside it.

Magnetic Characteristics (B-H curve)

Magnetic Characteristics(B-H curve) magnetism
Magnetic Characteristics(B-H curve)

The relation between B and H is not linear however (i.e. µr is not a constant for all values of H). The higher of H, the more the number of dipoles oriented. However, at still higher values of H, when all dipoles are orient themselves, there will be no further increase of intrinsic magnetisation on it. This is know as magnetic saturation.

Types of Magnetism – magnetism

Also Material may be classified into one of five categories depending on its magnetisation characteristics.

  1. Diamagnetic materials
  2. Paramagnetic materials
  3. Antiferromagnetic materials
  4. Ferromagnetic materials
  5. Ferromagnetic materials

Diamagnetic, Paramagnetic and Antiferromagnetic materials are also non-magnetic materials.

Also Ferromagnetic and Ferromagnetic materials are magnetic materials.

Also we will discuss more about types of magnetism in next article

5 thoughts on “Magnetisation Fundamentals”

  1. Janitha Dhananjaya

    It’s helpful to get quick idea about Magnetisation Fundamentals.
    Superb!!!
    Keep it up..!

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