Home » BASIC FUNDA » SUSCEPTIBILITY, CURIE POINT.

What is intensity of magnetization?
Intensity of magnetization, symbolized as I, of a magnetic material is defined as the magnetic moment per unit volume of the material.
This is also defined as the pole strength per unit area of cross section of the material.
Suppose m= pole strength in Weber,
A=unit cross section area in m2.
Intensity (I)=m/A Wb/ m2.
If, l=length of the bar, then magnetic moment, M =m X l.
So, Intensity, I = mxl/(Axl) = M/V = magnetic moment/volume.
Magnetic moment or magnetic dipole moment is a vector quantity and defined as the measure of the object’s tendency to align with a magnetic field. By this property the magnet is capable to exert an electric current as well as the torque.

SUSCEPTIBILITY:
The magnetic susceptibility of a material is equal to the ratio of the intensity of the magnetization (I) to the magnetizing force. It is denoted by chi (X).
So, ᵪ = I/H Henry/meter.
For this property of material we can say whether it is attracted or repealed by the magnetic field.
For diamagnetic substance, chi (X) less than 0.
• In case of paramagnetic substance 1> chi (X)> 0.
• In case of super paramagnetic and ferromagnetic substance chi (X)>>1
.

CURIE POINT:
If a magnetic material is heated by externally, after a certain temperature the magnetic strength of that material decrease to zero. That critical temperature is called Curie point of that material.
Temperature is inversely proportional to the magnetic field strength. So when we increase the temperature of a selected magnetic material, the molecules vibrate randomly and destroy the alignments. It reduces the magnetic strength. At a certain temperature when magnetic strength become zero is called Curie point.
In other words it is the temperature above which a ferromagnetic material becomes paramagnetic.