Sendust was invented circa 1936 by Hakaru Masumoto at Tohoku Imperial University in Sendai, Japan, as an alternative to permalloy for inductors in telephone networks.
The 85% iron, 9% silicon, 6% aluminium alloy combines permeability up to 140,000 with coercivity of about 5 A/m and saturation flux density up to 1 T.
It shows zero magnetostriction and zero magnetocrystalline anisotropy (K1 = 0), and its hardness suits abrasive duty such as magnetic recording heads.