Mangetic Dipole Moment

MAGNETIC   MATERIALS – DIPOLE MOMENT            
                      Materials which has got the ultimate capacity of attracting pieces of Iron, nickel, cobalt , dyasporium when they are subjected to external field can be noticed as an important property of magnetic materials.   Magnetic materials will not exist as a monopole they always exist as a dipole, because even if we break the magnetic material into pieces the tiny pieces of magnet will also behave as a dipole.   Actually the dipole in a magnet is formed due to two reasons
  1. Orbital Motion               2.   Spin motion of electron
We know that electron revolves round the nucleus in definite circular orbits and with consistent energy levels. If the path of this electrons is treated as circular current loop it   produces some electric force, due to the generation of this electrical force the size of the nucleus in the material gets distorted, as a result of this the shifting of   +ve and –ve charges will take place resulting in the formation of dipole. The moment of such dipole is known as   orbital magnetic dipole moment. Generally dipole moment can be defined as the product of pole strength and geometrical length of the   bar magnet . The unit of pole strength is Ampere-metre. In addition to the electron revolving round the nucleus in definite circular orbits it spins on its own axis, as a result of which the displacement of positive and negative charges takes place, the moment of such   dipoles is known as the spin magnetic dipole moment .
       
                         
  There is another type of magnetic moment called Nuclear magnetic moment where the absolute moment of nucles and electrons will take place.
Depending   on   the alignment of atoms and their response to the external magnetic field   at a given point of time magnetic materials can be broadly classified into 5 types.
  1. Diamagnetic materials.
  2. Ferromagnetic materials.
  3. Paramagnetic materials.
  4....