Write a short note on the following:-
 Ferrites

Hint: As we know that ferrite is usually named to the class of the ferromagnetic compounds whose general formula is $A{{B}_{2}}{{O}_{4}}$. Here A is a divalent cation and B is a trivalent cation. These are one of the most important and useful materials in the electronic industry and are usually classified as soft and hard ferrites. So we have to explain about ferrites in this question.

Complete answer:
Let us discuss about ferrites as follows:-
-Ferrites: These are the large class of oxides that contains a trivalent and a divalent cation of same or different metal which have been investigated as well as applied to a wide variety of fields. This field ranges from old technologies like circuitry, permanent magnets, magnetic recording and also microwave devices. The most recent developments in this field include bioimaging and gas sensing.
-These are the compounds whose general formula is $A{{B}_{2}}{{O}_{4}}$where A is a divalent cation and B is a trivalent cation. In almost all the structures of ferrites, oxide ion occupies the CCP sites whereas divalent cations occupy one-eighth of the tetrahedral voids. Also trivalent cations occupy almost half of the octahedral voids.
-These compounds do have spinel structure. An example of ferrite is given below:-
$MgA{{l}_{2}}{{O}_{4}}$ is a ferrite with a spinel structure. Here Magnesium (Mg) is a divalent cation and Aluminum (Al) is a trivalent cation.
-Hard ferrites generally have high coercivity due to which these are difficult to demagnetize. They are mainly used to manufacture permanent magnets.
-Soft ferrites do have low coercivity due to which they can easily change their magnetization and can act as conductors in external magnetic fields. They are basically used in the electronics industry to manufacture efficient magnetic cores which are known as ferrite cores.

Note:
Few more properties related to ferrites are given below:-
-Those materials which are formed by ferrite compounds are used as electromagnetic wave absorbers because absorbers of ferrite compounds usually have a broad frequency bandwidth in very ultrahigh frequency bands.
-Ferrite compounds generally possess high resistivity and permeability.