A question about antiferromagnetism in an external B field

In summary, antiferromagnetic materials exhibit magnetic hysteresis due to the coupling between the external magnetic field and the magnetization of the two sublattices. In the absence of an external field, the magnetization of the two sublattices cancel each other out, resulting in no net magnetization. However, when an external magnetic field is applied, the magnetization of the two sublattices becomes unequal, leading to a ferrimagnetic ordering. Once the external field is removed, the magnetization of the sublattices returns to their original state. This behavior is different from ferro and ferrimagnetic materials, as the hysteresis curve of an antiferromagnet passes through the origin but
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fluidistic
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At first I was wondering whether antiferromagnetic materials exhibit magnetic hysteresis. From what I could read on wikipedia, I think they should, but for a very strange reason. Indeed, in the absence of any external ##\vec B## field, the magnetization of the 2 different sublattices have the same magnitude but opposite direction and so the net magnetization vanishes. However, when an external magnetic field is applied, the net magnetization stops to vanish because the 2 sublattices have different magnitude. So that, if I understand well, we fall into the case of ferrimagnetism. In other words antiferromagnetism would be a magnetic order valid when no external $\vec B$ field is applied. As soon as an external ##\vec B## field exists, the material will turn into a ferrimagnetic ordering.
I do not understand why this would be the case. My intuition tells me it's due to the coupling between the external ##\vec B## field and the magnetization of the 2 sublattices. Can someone give me a reference or quick mathematical exhibition to point me out how the magnetization of each sublattice changes with respect to the external applied ##\vec B## field?
 
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In an antiferromagnet, the sub-lattices will return to having the same magnetisation as before applying the magnetic field once it is switched off. In an antiferromagnet, the ions having anti-parallel spins are equivalent, whence their magnetism compensates. In a ferrimagnet, the sub-lattices correspond to ions on non-equivalent sites in a lattice, hence the magnetic moment will not vanish even if no field is applied.
 
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DrDu said:
In an antiferromagnet, the sub-lattices will return to having the same magnetisation as before applying the magnetic field once it is switched off.
Ok, so far so good. This is basically what I had understood in that antiferromagnetism has the same behavior than ferrimagnetism except when the external ##\vec B## field vanishes.

So, if I understand well, the hysteresis curve of an antiferromagnet is different than the ones of ferro and ferrimagnetic materials in that the curve passes at the origin (0 magnetization when there is 0 magnetic field applied), but everywhere else, hysteresis occurs. Is this correct?
 

1. What is antiferromagnetism?

Antiferromagnetism is a phenomenon in which the magnetic moments of neighboring atoms or ions align in opposite directions, resulting in zero net magnetization. This is different from ferromagnetism, where the magnetic moments align in the same direction.

2. How does antiferromagnetism behave in an external magnetic field?

In an external magnetic field, the magnetic moments in an antiferromagnet will rotate and align in the direction of the field, causing a slight increase in magnetization. However, this increase is much smaller compared to ferromagnets, due to the opposite alignment of the moments.

3. What factors affect the strength of antiferromagnetism in an external magnetic field?

The strength of antiferromagnetism in an external magnetic field is affected by the strength of the external field, the distance between the atoms or ions, and the exchange coupling between the magnetic moments.

4. Can antiferromagnetism be used in any practical applications?

Yes, antiferromagnetic materials have been used in various technologies such as magnetic sensors, memory devices, and spintronic devices. They are also being researched for potential applications in quantum computing.

5. How is antiferromagnetism different from other types of magnetism?

Antiferromagnetism is different from ferromagnetism in that the magnetic moments cancel each other out, resulting in zero net magnetization. It is also different from paramagnetism, where the magnetic moments are randomly oriented and can be easily influenced by an external field.

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