Amorphous magnetostrictive alloy with low cobalt content and method for annealing same

US6018296A · kind A · utility

Assignee

• Vacuumschmelze GmbH & Co. KG · DE

Inventor

• Giselher Herzer · Bruchköbel, DE

Key dates

• Filing date: Jul 9, 1997
• Grant date: Jan 25, 2000
• Expiry date: Jul 9, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D6/007
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A resonator for use in a marker in a magnetomechanical electronic article surveillance system is formed by a planar strip of an amorphous magnetostrictive alloy having a composition Fe.sub.a Co.sub.b Ni.sub.c Si.sub.x B.sub.y M.sub.z wherein a, b, c, x, y, and z are at % and a+b+c+x+y+z=100, a+b+c>75, a>15, b<20, c>5 and z<3, wherein M is at least one element selected from the group consisting of C, P, Ge, Nb, Mo, Cr and Mn, the amorphous magnetostrictive alloy having a resonant frequency f.sub.r which is a minimum at a field strength H.sub.min and having a linear B-H loop up to at least a field strength which is about 0.8 H.sub.min and a uniaxial anisotropy perpendicular to the plane of the strip with an anisotropy field strength H.sub.k which is at least as large as H.sub.min and, when driven by an alternating signal burst in the presence of a bias field H.sub.b, producing a signal at the resonant frequency having an amplitude which is a minimum of approximately 50% of a maximum obtainable amplitude relative to the bias field H.sub.b in a range of H.sub.b between 0 and 10 Oe.