Question

What is meant by ferrimagnetism? Give any two examples.

Answer 1

Hint: It is related to something that deals with the magnetic dipoles and its alignment. It is related to the number of unpaired electrons present in the element or a compound. A behavioral nature of few substances in the presence and absence of magnetic fields.

Complete answer:
We know that if a substance is placed in the presence of a magnetic field it may either repel or get attracted towards the magnetic field. This is the basic phenomenon we know about how substances behave in the presence of magnetic fields. But if we study more or go deeper about the reason for such behavior we come across few terms like magnet dipoles, its alignment and its nature in the presence and absence of the magnetic field.
-Magnetic dipole- A magnetic dipole is just a tiny magnet which has a dimension of microscopic to subatomic particle level and is equivalent to an electric current flowing through a loop. Electrons which are spinning in their axis, electrons which are revolving around the nuclei and rotating positively charged nuclei are all magnetic dipoles.
-Ferrimagnetism-It is the phenomenon exhibited by the ferrites, in which the magnetic dipoles of the neighboring atoms are arranged in anti-parallel fashion and unequal in magnitude.
The phenomenon is mainly seen in solids and it is the type of permanent magnetism in which the magnetic dipoles associated with the individual atoms aligns spontaneously either
- In the same direction of the applied field as in ferromagnetism or
- In the antiparallel direction to the applied magnetic field as in anti-ferromagnetism
As some of the atoms which is considered as tiny magnets are arranged in anti-parallel fashion cancels out and hence ferromagnetism is less in dimension considered to the ferromagnetism in which all dipole arrange in parallel fashion to the magnetic field and retains the magnetic field even after the removal of the magnetic field.

-Examples of ferromagnetic substances are magnetite ($F{{e}_{3}}{{O}_{4}}$), iron oxides with other elements like Co. Ni, Mn


Note: Paramagnetic materials too show such behavior in the presence of magnetic field but they lose the magnetic property as soon as the magnetic field is removed. Paramagnetic materials have low or small force of attraction in the presence of magnetic field whereas ferrimagnetic materials are strongly attracted towards the magnetic field but ferromagnetic is stronger than ferromagnetic and retains the magnetic property.