Which Alloys Have Stronger Ferromagnetism than Pure Iron?

Several iron-based alloys exhibit stronger ferromagnetism than pure iron due to atomic arrangements that enhance domain alignment. Key examples include:

1. Permalloy (Nickel–Iron alloy) – Contains about 80% nickel and 20% iron. It shows high magnetic permeability, making it extremely sensitive to magnetic fields. Used in transformers, magnetic shielding, and recording heads.
2. Alnico (Aluminum–Nickel–Cobalt–Iron alloy) – Combines aluminum, nickel, cobalt, and iron. It produces strong, permanent magnets with high coercivity and stability at high temperatures. Common in loudspeakers and electric motors.
3. Silicon steel (Iron–Silicon alloy) – Adding 3–4% silicon reduces energy loss and increases magnetic efficiency. Widely used in transformer cores and electric machinery.
4. Supermalloy – A refined version of permalloy with molybdenum added. It offers even higher permeability and low coercivity, ideal for precision magnetic instruments.

These alloys outperform pure iron because alloying elements improve crystal structure and reduce domain wall energy, enhancing magnetization.