Every substance around us has some magnetic properties in it. Different types of materials show different properties in the presence of a magnetic field. The magnetic properties of a substance originate from the electrons present in the atoms or molecules. Every electron in an atom behaves like a small magnet. Electrons can also be referred to as small loops of current which retain their magnetic moment.
These magnetic moments come from two types of motion of electrons:
- The orbital movement around the nucleus of an atom.
- When the electron spins around its own axis.
On the basis of the magnetic properties solids can be classified as follows:
|Properties||Description||Alignment of magnetic dipoles||Examples||Application|
|Diamagnetic||They are weakly repelled by the magnetic fields||All the electrons in the orbitals are paired and are completely filled.||NaCl, Benzene||Behaves like an insulator.|
|Paramagnetic||They are weakly attracted by the magnetic fields.||Contains at least one unpaired electron in the orbital.||O2, Cu2+ etc.||Electronic appliances|
|Ferromagnetic||Strongly attracted by the magnetic field.
The can be magnetised permanently
|Consists of unpaired electrons, all having the same direction||Cobalt, nickel, CrO2 etc.||CrO2 is commonly used in making cassette recorder.
|Antiferromagnetic||Net magnetic moment is zero.||Dipole moments are arranged in a compensatory way||NiO, MnO, V2O3 etc.||–|
|Ferrimagnetic||Possess small net magnetic moments||Unequal number of parallel and antiparallel arrangement of magnetic moments||Fe3O4||–|
Graphs showing the variation of magnetic properties on changing temperature:
In paramagnetic material, with the increase in the magnetic field, the magnetization of the material increases. When the material is heated the magnetization starts decreasing, so the magnetization of the material is inversely proportional to temperature. This relationship is known as Curie’s law.
M = C×(B/T)
Where, M = magnetization of the material
C= Curie’s constant
B= applied magnetic field
Fig. Graphs showing the effect of temperature on magnetization of materials.
In this article, we discussed the magnetic properties of solids. To know about the electrical properties and dielectric properties of solids. For more information download BYJU’S-The Learning App.