Permalloy, trademark of the Western Electric Company for nickel-iron alloys having much higher magnetic permeability than iron alone. It is widely used for fabricating the thin pieces that are laminated to form transformer cores. The proportion of nickel may range from 35 to 90 percent, depending on the properties desired, and is about 78 percent for low-power transformers.
Permalloy is a nickel–iron magnetic alloy, with about 80% nickel and 20% iron content. Invented in 1914 by physicist Gustav Elmen at Bell Telephone Laboratories, it is notable for its very high magnetic permeability, which makes it useful as a magnetic core material in electrical and electronic equipment, and also in magnetic shielding to block magnetic fields. Commercial permalloy alloys typically have relative permeability of around 100,000, compared to several thousand for ordinary steel.
Geez, Western Electric / Bell Labs invented permalloy... shocker!
Originally invented and used to speed-up Trans-Atlantic telegraph communication Four-Fold!