Antiferromagnetism

Antiferromagnetism is present in ceramics produced from transition metals and cancels the magnetization of these substances.

Conventional magnets are ferromagnetic materials
Where does magnetism come from?

Magnetism is a property present in atoms and molecules and is related to the interaction of orbital angular momentum with electron spin. The way these two quantities are spatially related in atoms is decisive for the macroscopic magnetic behavior of the material.

There are regions within materials called magnetic domains. In these regions, the resulting magnetic moment points in a single direction. The way these domains meet (aligned or not, for example) determines whether a body can be attracted by a magnet or even repelled.

magnetic materials

There are several types of materials with magnetic properties that are used for the most varied technological purposes. Among the magnetic behaviors , we can highlight ferromagnetism, paramagnetism, diamagnetism and antiferromagnetism .

What is antiferromagnetism?

The ferromagnetic property ensures that materials have their magnetic domains aligned in a preferred direction in the presence of an external magnetic field , and can be magnetized or attracted by magnets. An example of this type of material is iron .

If the magnetic domains are aligned in the same direction, but in opposite directions and in pairs, the total resulting magnetic moment will be zero, in which case we say that the material is antiferromagnetic .

In the absence of external magnetic fields, these materials do not have their own magnetic field and can lose their antiferromagnetic state when they reach the Neel Temperature, when they start to behave as paramagnetic materials.

Antiferromagnetic materials are generally ceramics produced using transition metals. Some examples of antiferromagnetic materials are: MnO (Manganese Oxide), MnF 2 (Manganese Fluoride), FeO (Iron Oxide), NiO (Nickel Oxide) and CoO (Cobalt Oxide).

In the following figure, there is a diagram that shows the relationship between the magnetic moments present in materials and which type of magnetic property originates from this interaction:

Technological applications of antiferromagnetic materials

Antiferromagnetic materials are particularly interesting because, at low temperatures, some of them start to show a superconducting behavior , that is, these materials, under certain conditions, have zero electrical resistance, being able to transmit any electric current intensities without loss of energy through dissipation in reason for the Joule effect.

Related Articles

Leave a Reply

Your email address will not be published.

Check Also
Close
Back to top button