Magnetic ordering: identifying the characteristic temperature in antiferromagnets In antiferromagnetic materials, the plot of magnetic susceptibility versus temperature exhibits a sharp maximum at a specific temperature. What is this temperature called?

Introduction / Context:
Different magnetic materials undergo ordering transitions characterized by distinctive temperatures. Ferromagnets lose spontaneous magnetization at the Curie temperature, while antiferromagnets lose antiparallel order at the Néel temperature. Recognizing which temperature applies to which material class is essential in magnetism.

Given Data / Assumptions:

• Material is antiferromagnetic below a certain temperature.
• Magnetic susceptibility χ(T) shows a peak at the transition.
• No external complications such as spin glass behavior are assumed.

Concept / Approach:
Antiferromagnetic ordering consists of sublattices with opposing moments. As temperature rises, thermal agitation disrupts this order. At the Néel temperature T_N, long-range antiparallel alignment collapses, and above T_N the material often follows a Curie–Weiss-like law with a negative Weiss constant.

Step-by-Step Solution:
Identify the material class: antiferromagnet.Recall the hallmark temperature for antiferromagnets is T_N, the Néel temperature.At T_N, χ(T) typically peaks (for many AFMs) as order is lost.Therefore select “Néel temperature”.

Verification / Alternative check:
Experimental χ(T) curves (e.g., MnO, Fe2O3 variants) show susceptibility maxima at T_N; literature consistently labels this the Néel temperature.

Why Other Options Are Wrong:
Curie temperature pertains to ferromagnets; “Weiss temperature” is a parameter in Curie–Weiss law, not the AFM transition name; “Bitter temperature” is not a standard magnetic transition term.

Common Pitfalls:
Confusing ferromagnetic and antiferromagnetic transitions; assuming all magnets use the Curie label.

Final Answer:
Néel temperature