Difficulty: Easy
Correct Answer: No, above the Curie temperature the material becomes paramagnetic and hysteresis vanishes
Explanation:
Introduction / Context:Ferromagnetic materials show domain ordering that produces remanence and coercivity — the ingredients of magnetic hysteresis. Temperature strongly influences this ordering through thermal agitation and exchange interactions.
Given Data / Assumptions:
Concept / Approach:Below T_C, exchange coupling aligns spins into domains, yielding non-zero remanent magnetization and coercive field — a hysteresis loop appears when cycling H. Above T_C, thermal energy overcomes exchange alignment; the material becomes paramagnetic with zero remanence and negligible coercivity, so the loop collapses to a reversible line through the origin.
Step-by-Step Solution:
Identify temperature region: T < T_C → ferromagnetic (domains, hysteresis).Increase temperature: approach T_C → loop shrinks as magnetization decreases.For T ≥ T_C: paramagnetic behavior; no hysteresis loop (no remanence or coercivity).Verification / Alternative check:
Experimental M–H curves across T_C show the loop area tending to zero at and above T_C.Why Other Options Are Wrong:
Saying hysteresis exists at all temperatures contradicts well-established phase behavior.Other distractors are physically nonsensical (e.g., 'below absolute zero').Common Pitfalls:
Confusing ferromagnetic with ferrimagnetic or antiferromagnetic transitions; each has its own critical temperature but hysteresis still collapses in the paramagnetic state.Final Answer:
No, above the Curie temperature the material becomes paramagnetic and hysteresis vanishes
Discussion & Comments