Question

Which has highest magnetic susceptibility?

• A. Diamagnetic
• B. Paramagnetic
• C. Ferromagnetic
• D. Antiferromagnetic

Hint:

The susceptibility of ferromagnetic materials is not only large but also non-linear and depends on the history of the applied magnetic field (hysteresis effect).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify which class of magnetic materials has the highest magnetic susceptibility ($\chi$).

Step 2: Key Formula or Approach:
Magnetic susceptibility is defined as:
\[ \chi = \frac{M}{H} \]
where $M$ is the induced magnetization and $H$ is the applied magnetic field strength.

Step 3: Detailed Explanation:

• Diamagnetic materials: Have a very small, negative susceptibility ($\chi \approx -10^{-5}$).

• Paramagnetic and Antiferromagnetic materials: Have a small, positive susceptibility ($\chi \approx 10^{-5}$ to $10^{-3}$).

• Ferromagnetic materials: Have extremely large, positive susceptibility (ranging from $10^3$ to $10^5$ or higher).

• Ferromagnetic materials contain permanent magnetic dipoles that are strongly aligned parallel to each other within domains due to quantum mechanical exchange coupling. Even a weak external field can easily cause these domains to align, resulting in massive magnetization ($M$) and thus a very high susceptibility value.

Step 4: Final Answer:
Ferromagnetic materials have the highest magnetic susceptibility.