The antiferromagnetic crystals undergo a transition to the paramagnetic state at a temperature called the Néel temperature. Above it, in the paramagnetic state, the dipoles point in random directions due to the predominance of thermal agitation, producing a zero total magnetization. Below the Néel temperature in antiferromagnetic state, the total magnetization is also zero, but for another reason. In the antiferromagnetic state, the lattice formed by magnetic atoms is divided into two or more equivalent sublattices, each presenting a spontaneous magnetization in a certain direction. The interaction between the dipoles causes a magnetic ordering such that the vector sum of the spontaneous magnetization of the sublattice vanishes, which defines the antiferromagnetic state.