Question

Above Curie temperature :

• A. a ferromagnetic substance becomes paramagnetic
• B. a paramagnetic substance becomes diamagnetic
• C. a diamagnetic substance becomes paramagnetic
• D. a paramagnetic substance becomes ferromagnetic

Answer 1

The Correct Option is A

To understand the transition of a ferromagnetic substance above the Curie temperature, we need to delve into the concepts of magnetism in materials.

Concept: In the realm of magnetism, materials can be categorized based on their magnetic properties as ferromagnetic, paramagnetic, or diamagnetic. Ferromagnetic materials, like iron, exhibit strong magnetic properties due to the alignment of their magnetic domains. However, this property is temperature-dependent.

Curie Temperature: The Curie temperature (or Curie point) is a critical temperature above which the ferromagnetic properties of a material change. At this temperature, the thermal energy becomes sufficient to disrupt the alignment of the magnetic domains.

1. Below the Curie Temperature: In ferromagnetic materials, the magnetic moments of atoms are aligned parallel due to strong exchange coupling, displaying permanent magnetism.
2. Above the Curie Temperature: The thermal energy becomes greater than the magnetic energy, causing the magnetic domains to become randomly oriented. Consequently, the material loses its ferromagnetic properties and behaves like a paramagnetic material, which means it is weakly attracted by a magnetic field and does not retain magnetic properties when the external field is removed.

Conclusion: Hence, when we increase the temperature of a ferromagnetic substance above its Curie temperature, it undergoes a transition and becomes paramagnetic.

Correct Answer: A ferromagnetic substance becomes paramagnetic.