‘Magneto-acoustic marker for electronic article surveillance having reduced size and high signal amplitude’

US6359563B1 · kind B1 · utility

Assignee

• Vacuumschmelze GmbH & Co. KG · DE

Inventor

• Giselher Herzer · Bruchköbel, DE

Key dates

• Filing date: Feb 10, 1999
• Grant date: Mar 19, 2002
• Expiry date: Feb 10, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B13/2442
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A resonator, having a width no larger than about 13 mm, for use in a marker containing a bias element which produces a bias magnetic field in a magnetomechanical electronic article surveillance system is produced from annealed ferromagnetic ribbon having a basic composition FeaCobNicSixByMz wherein a, b, c, x, y and z are in at %, wherein M is one or more glass formation promoting elements and/or one or more transition metals, and wherein 15≦a≦30, 6≦b≦18, 27≦c≦55, 0≦x≦10, 10≦y≦25, 0≦z≦5, 14≦x+y+z≦25, such that a+b+c+x+y+z=100. The ferromagnetic ribbon is annealed in a magnetic field oriented perpendicularly to the ribbon axis and/or while applying a tensile stress to the ribbon along the ribbon axis. Single resonator or multiple resonator assemblies can be formed by cutting elements from the annealed ribbon. If multiple resonators are formed, the elements are placed in registration. The resulting narrow (6 mm wide) resonator has properties comparable to the properties of wider resonators, such as the conventional 12.7 mm wide resonator.