Introduction / Context:
Magnetic behavior of materials arises from electron spins and orbital motions. Whether a solid exhibits a net permanent moment depends on the presence of unpaired spins and cooperative ordering. This question checks the basic classification when no permanent dipoles exist in the absence of a field.
Given Data / Assumptions:
- No permanent magnetic dipoles; all atomic or molecular moments cancel out in zero field.
- Consider response in a weak, applied magnetic field.
- Temperature is not driving long-range magnetic order (no ferromagnetic or ferrimagnetic states).
Concept / Approach:
Diamagnetic materials have all electrons paired; they exhibit an induced magnetic moment opposite to the external field due to Lenz-like response of orbital motion, giving a small negative susceptibility. Paramagnets have unpaired electrons that align weakly with the field (positive susceptibility) but no permanent magnetization without a field. Ferromagnets and ferrimagnets show spontaneous ordering and domain behavior leading to permanent dipoles.
Step-by-Step Solution:
Identify the absence of permanent dipoles → rules out ferro-, ferri-, and antiferromagnets in their ordered states.Paramagnets still possess permanent atomic moments (unpaired spins) even if disordered → not suitable.Materials with paired electrons only exhibit diamagnetism with negative susceptibility.
Verification / Alternative check:
Examples: bismuth, copper, and superconductors (perfect diamagnetism in the Meissner state) demonstrate diamagnetic behavior.
Why Other Options Are Wrong:
Paramagnetic: contains permanent dipoles from unpaired spins.Ferromagnetic/Ferrimagnetic: possess domain magnetization and remanence.Antiferromagnetic (not listed in stem but as an option): still has ordered sublattice spins, although net moment may cancel; not “no permanent dipoles.”
Common Pitfalls:
Equating “no net moment” with “no dipoles”; antiferromagnets have opposing sublattice dipoles, not the absence of dipoles.
Final Answer:
Diamagnetic
Discussion & Comments