Define the following :
Antiferromagnetic substances and antiferromagnetism

Explanation

Antiferromagnetic substances and antoferromagnetism
The property by virtue of which certain substances which are expected to be ferromagnetic on the basis of their domain structure but are not attracted by a magnetic, is called antiferromagnetism and such substances are called anti-ferromagnetic substances. In these substances domains are oppositely oriented and cancel out each other.s magnetic moment.
Examples : `MnO,NiO,MnF_(2)` etc.
However, all magnetically ordered solids (ferromagnetic, anti ferromagnetic and ferrimagnetic) transform to the paramagnetic state at high temperature due to randomisation of spins.