Question

Antiferromagnetic materials have magnetic susceptibility in the range:

• A. \(-10^{-3}\) to \(-10^{-5}\)
• B. \(10^{-2}\) to \(10^{-5}\)
• C. \(-10^{2}\) to \(-10^{5}\)
• D. \(10^{2}\) to \(10^{5}\)

Hint:

Remember the general orders of magnitude for volume magnetic susceptibility (\(\chi_v\)):

Diamagnetic: \(\approx -10^{-5}\) (small, negative)
Paramagnetic & Antiferromagnetic: \(\approx +10^{-5}\) to \(+10^{-3}\) (small, positive)
Ferromagnetic: \(>> 1\) (large, positive)

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Antiferromagnetic materials are those in which the magnetic moments of adjacent atoms align in an antiparallel configuration. In the absence of an external magnetic field, the net magnetization is zero. We need to identify the typical range of their magnetic susceptibility (\(\chi\)).
Step 2: Detailed Explanation:
When an external magnetic field is applied to an antiferromagnetic material, it causes a slight canting of the antiparallel moments, resulting in a small, net magnetization in the direction of the field. This means their magnetic susceptibility is small and positive. It is generally of the same order of magnitude as that of paramagnetic materials.
Let's analyze the given options:

(A) \(-10^{-3}\) to \(-10^{-5}\): This range is small and negative, which is characteristic of diamagnetic materials.
(B) \(10^{-2}\) to \(10^{-5}\): This indicates a range of small positive values (assuming it means the values between \(10^{-5}\) and \(10^{-2}\)). This range is consistent with the small, positive susceptibility of both paramagnetic and antiferromagnetic materials.
(C) \(-10^{2}\) to \(-10^{5}\): This is a large negative range and is not physically realistic for susceptibility.
(D) \(10^{2}\) to \(10^{5}\): This is a large positive range, characteristic of ferromagnetic materials.

Step 3: Final Answer:
By elimination, the only plausible range for the small, positive susceptibility of antiferromagnetic materials is the one given in option (B).