Question

Are antiferromagnetic materials magnetic?

Answer 1

Explanation

1. Antiferromagnetic materials are those materials that when kept in the presence of a strong magnetic field, get weakly magnetized in the direction of the magnetic field.
2. These do not have an external magnetic moment.
3. At low temperatures, antiferromagnetic materials will not respond to the external field since the antiparallel orientation is rigidly maintained.
4. As the temperature is increased some of the atoms will break free and arrange in the direction of the external magnetic field.
5. A weak magnetism is created in the material and this increases and reaches its peak at the Neel temperature.
6. Chromium, is an antiferromagnetic material, below the Neel temperature of 37 °C, under the applied magnetic field, the neighboring atomic moments are antiparallel to each other, which leads to a zero net magnetization; therefore, such kind of materials are not sensitive to a magnetic field.
7. Neel temperature$T_N$, is a temperature limit at which magnetism reduces and antiferromagnetic substance materials become paramagnetic.

$X_M=\frac{C}{T+T_N}$(where, $X_M$ is magnetic susceptibility, $T$ is temperature, $T_N$ is Neel Temperature and $C$ is Curie's constant.)

Hence, Antiferromagnetic materials are not magnetic.