Amorphous antipilferage marker and detection system comprising same

Claim 2

For use in a magnetic theft detection system, a marker adapted to generate magnetic fields at -frequencies that are harmonically related to an incident magnetic field applied within an interrogation zone and have selected tones that provide said marker with signal identity, said marker characterized as an elongated, ductile strip of amorphous ferromagnetic material and capable of retaining its signal identity after being flexed or bent.

Claim 3

A marker as recited in claim 1, said marker having at least one magnetizable portion integral therewith, the magnetizable portion having coercivity higher than that of said amorphous material.

Claim 4

A marker as recited in claim 2, wherein said- magnetizable portion is adapted to be magnetized to bias said strip and thereby decreases the amplitude of the magnetic fields generated by said marker.

Claim 5

A marker as recited in claim 2, wherein said magnetizable portion comprises a crystalline region of said material.

Claim 6

A marker as recited in claim 3, wherein said decrease in amplitude of magnetic fields generated by said marker causes said marker to lose its signal identity.

Claim 7

A magnetic theft detection system marker for generating magnetic fields at frequencies that are harmonically related to an incident magnetic field applied within an interrogation zone and have selected tones that provide said marker with signal identity, characterized in that: a. said marker is an elongated, ductile strip of amorphous ferromagnetic material; and b. said,marker retains its signal identity after being flexed or bent.

Claim 8

A magnetic theft detection system marker for generating magnetic fields at frequencies that are harmonically related to an incident magnetic field applied within an interrogation zone and have selected tones that provide said marker with signal identity, characterized in that: a. said marker is an elongated, ductile strip of amorphous ferromagnetic material; and b. said,marker retains its signal identity after being flexed or bent.

Claim 9

A magnetic detection system responsive to the presence of an article within an interrogation zone, characterized in that the system is provided with: a. means for defining an interrogation zone; b. means for generating a magnetic field within said interrogation zone; c. a marker secured to an article appointed for passage through said interrogation zone, said marker being an elongated, ductile strip of amorphous ferromagnetic metal capable of producing magnetic fields at frequencies which are harmonics of the frequency of an incident field; and d. detecting means for detecting magnetic field variations at selected tones of said harmonics produced in the vicinity of the interrogation zone by the presence of the marker therewithin, said selected tones providing said marker with signal identity and said marker retaining said signal identity after being flexed or bent.

Claim 10

A magnetic detection system responsive to the presence of an article within an interrogation zone, characterized in that the system is provided with: a. means for defining an interrogation zone; b. means for generating a magnetic field within said interrogation zone; c. a marker secured to an article appointed for passage through said interrogation zone, said marker being an elongated, ductile strip of amorphous ferromagnetic metal capable of producing magnetic fields at frequencies which are harmonics of the frequency of an incident field; and d. detecting means for detecting magnetic field variations at selected tones of said harmonics produced in the vicinity of the interrogation zone by the presence of the marker therewithin, said selected tones providing said marker with signal identity and said marker retaining said signal identity after being flexed or bent.

Claim 11

A magnetic theft detection system, characterized by a marker adapted to generate magnetic fields at frequencies that are harmonically related to an incident magnetic field applied within an interrogation zone and have selected tones that provide said marker with signal identity, said marker being an elongated, ductile strip of amorphous ferromagnetic material having a composition consisting essentially of the formula (Ta X Tb 1-X ) M Ba 1-M , where Ta is at least one of iron and cobalt, Tb is selected from the group consisting of nickel, molybdenum, vanadium, chromium and copper and mixtures thereof, Ba is at least one of boron, phosphorus, carbon, silicon, nitrogen, germanium and aluminum, x ranges from about 20-100 atom percent and M ranges from about 70-85 atom percent.

Claim 12

A magnetic theft detection system, characterized by a marker adapted to generate magnetic fields at frequencies that are harmonically related to an incident magnetic field applied within an interrogation zone and have selected tones that provide said marker with signal identity, said marker being an elongated, ductile strip of amorphous ferromagnetic material having a composition consisting essentially of the formula (Ta X Tb 1-X ) M Ba 1-M , where Ta is at least one of iron and cobalt, Tb is selected from the group consisting of nickel, molybdenum, vanadium, chromium and copper and mixtures thereof, Ba is at least one of boron, phosphorus, carbon, silicon, nitrogen, germanium and aluminum, x ranges from about 20-100 atom percent and M ranges from about 70-85 atom percent.