Magnetic materials: The property describing a material’s ability to stay magnetized after the magnetizing force is removed is called

Introduction / Context:
Magnetic material properties determine performance in permanent magnets, memory elements, and motors. It is important to distinguish among permeability, reluctance, hysteresis, and retentivity when selecting or analyzing magnetic materials.

Given Data / Assumptions:

• After removing the magnetizing force (H → 0), some materials retain a nonzero flux density B.
• We are naming the specific property that quantifies this behavior.

Concept / Approach:
Retentivity (or residual flux density, Br) measures how much magnetization remains when the magnetizing force is reduced to zero. Hysteresis refers to the lag between B and H and the energy loss in one cycle, visualized as the hysteresis loop. Reluctance is the magnetic analog of resistance (opposition to flux). Permeability measures how readily a material supports the formation of magnetic flux.

Step-by-Step Solution:

Verification / Alternative check:
Refer to a B-H curve: At H = 0 after driving to saturation, the vertical intercept is Br, which reflects retentivity. Materials like hard ferrites have large Br; soft magnetic materials have small Br to allow easy demagnetization.

Why Other Options Are Wrong:

• Hysteresis: Describes loop energy loss and lag, not specifically “remaining magnetization”.
• Reluctance: Unit At/Wb; relates to flux opposition in a magnetic path.
• Permeability: Unit H/m; governs B = μ * H, not residual magnetism after H is removed.

Common Pitfalls:

• Using “hysteresis” when the question asks about retained magnetization explicitly.
• Confusing retentivity (Br) with coercivity (Hc), which is the reverse field needed to reduce B to zero.

Final Answer:
retentivity