Abstract: A tag or marker is disclosed which comprises a substrate; an `active` magnetic material which is a soft magnetic material having a high magnetic permeability and a low coercive force; and a deactivating material which is a hard or semi-hard magnetic material having a moderate or high coercive force and a moderate magnetic permeability, whereby the deactivating material, when subjected to a sufficiently high magnetising force, is able to clamp the magnetic properties of the `active` material so as to deactivate the `active` material. The deactivating material in the tag or marker is electrodeposited nickel with a planar crystal grain structure.

Abstract: A method of modifying the magnetic properties of a thin film of a magnetically active material is provided which comprises forming surface modulations on the material in order to partition it into regions which display at least some degree of mutual magnetic independence. The resulting modified thin film may be used as a marker or tag in an anti-pilferage or article location system. The surface modulations formed on the material in the anti-pilferage or article location marker serve to enhance the response of the marker when used in an anti-pilferage or article location system.

Abstract: A tag or marker is disclosed which comprises a substrate; an `active` magnetic material which is a soft magnetic material having a high magnetic permeability and a low coercive force; and a deactivating material which is a hard or semi-hard magnetic material having a moderate or high coercive force and a moderate magnetic permeability, whereby the deactivating material, when subjected to a sufficiently high magnetising force, is able to clamp the magnetic properties of the `active` material so as to deactivate the `active` material. The tag or marker is characterised in that the deactivating material is formed by an electrodeposition process, and in that the deactivating layer is nickel.

Abstract: An electronic article surveillance system is provided that comprises a core-wound drive coil which produces an AC magnetic interrogation field, and a detection coil provided on one side with at least one element of a screening material, which detection coil detects an AC magnetic response field generated by a magnetically active tag or marker which is subjected to the interrogation field when the tag or marker comes in proximity with the detection coil. The screening material may take the form of an open-ended electrically conductive box having an insulating gap along its length, or a laminate consisting of a plurality of metal foils interleaved with an electrically insulating material. The invention provides well-defined flux control for the detection coil which preventsinterference from unwanted external magnetic fields.

Abstract: Both an antipilferage marker and a system therefor is provided that uses magnetic spin resonance phenomena to generate unique and identifiable signals. The marker generally comprises a substrate which supports a material that generates and identifiable signal as a result of either nuclear magnetic resonance, nuclear quadrupole, electron spin resonance, electron paramagnetic resonance, ferromagnetic resonance, ferrimagnetic resonance, antiferrimagnetic resonance, domain wall resonance or spin wave resonance or spin-echoes. A magnetic material is further provided on the substrate for applying a magnetic field to the resonant material. In the system of the invention, a microwave or radio frequency source emits electromagnetic radiation which is absorbed by the resonant material which in turn reemits electromagnetic radiation having a specific and readily detectable frequency signature.

Abstract: Magnetic devices are disclosed which include an article comprising a substrate and a thin coating of a magnetic material, in which:(a) said substrate is a flexible, laminar material; (b) said magnetic material is an amorphous metal glass of high intrinsic magnetic permeability, with low or substantially zero magnetostriction, and with low coercivity; and (c) said thin coating of a magnetic material is not greater than 6 microns in thickness. This article can be used as, or to make, an antipilferage tag or marker. Deactivation materials and configurations are also disclosed, as well as techniques, in particular sputtering or PVD, for producing such a tag.

Abstract: This application discloses a method of recognizing and/or locating preselected categories of articles, which comprises applying to the articles a plurality of magnetic elements in predetermined associations (e.g. with predetermined numbers of magnetic elements and with predetermined spacings between said elements), whereby when the articles are caused to move relative to a predetermined interrogating magnetic field, each particular association of magnetic elements gives rise to a magnetic signature whereby the article or category of article carrying each of the predetermined associations can be recognized and/or located. A series of tags or markers for use in such a method, as well as a system for determining the location and/or identity of an article within an article conveying network, are also disclosed.