Magnetic glassy alloys for electronic article surveillance

Abstract

A glassy metal alloy consists essentially of the formula CoaNibFecMdBeSifCg, where M is at least one element selected from the group consisting of Cr, Mo, Mn and Nb, “a-g” are in atom percent and the sum of “a-g” equals 100, “a” ranges from about 25 to about 60, “b” ranges from about 5 to about 45, “c” ranges from about 6 to about 12, “d” ranges from about 0 to about 3, “e” ranges from about 5 to 25, “f” ranges from about 0 to about 15 and “g” ranges from about 0 to 6, said alloy having a value of the saturation magnetostriction between −3 ppm and +3 ppm. The alloy can be cast by rapid solidification from the melt into ribbon, sheet or wire form. The alloy exhibits non-linear B—H hysteresis behavior in its as-cast condition. The alloy is further annealed with or without magnetic field at temperatures below said alloy's first crystallization temperature, having non-linear B—H hysteresis loops. The alloy is suited for use as a magnetic marker in electronic article surveillance systems utilizing magnetic harmonics.

Dependencies are inferred from the claim text.