Glass-coated amorphous magnetic mircowire marker for article surveillance

A magnetic marker for use in electronic article surveillance (EAS) system, the marker comprising a magnetic element having a single microwire piece, which is made of an amorphous metal-containing material with glass coating and has substantially zero magnetostriction, coercivity substantially less than 10 A/m and permeability substantially higher than 20000, a core diameter of the microwire piece being of about 45-60 μm.

A magnetic marker for use in electronic article surveillance (EAS) system, the marker comprising a magnetic element including at least three microwire pieces, each of the microwire pieces being made of an amorphous metal-containing material with glass coating and having substantially zero magnetostriction, coercivity substantially less than 10 A/m and permeability substantially higher than 20000, a core diameter of the microwire piece substantially not exceeding 30 μm.

An electronic article surveillance system utilizing a marker mounted within an article to be detected by the system when entering an interrogation zone, the system comprising a frequency generator coupled to a coil for producing an alternating magnetic field within said interrogation zone, a magnetic field receiving coil, a signal processing unit and an alarm device, wherein said marker comprises a magnetic element comprising a predetermined number of microwire pieces made of an amorphous metal-containing material with glass coating and having substantially zero magnetostriction, coercivity substantially less than 10 A/m and permeability substantially higher than 20000, wherein the marker has one of the following designs:

• it has the single microwire piece with the core diameter of about 45-60 μm;
• and
• it has at least three microwire pieces each with the core diameter substantially not exceeding 30 μm.