Multibit tag using Barkhausen effect
First Claim
Patent Images
1. A multibit identification tag for storing digital data, comprising:
- a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field,wherein each of said plurality of magnetic structures includes;
a substrate;
an Barkhausen jump magnetic material deposited on said substrate;
a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; and
a hard magnetic layer deposited onto said first nonmagnetic spacer layer, a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and
a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer,wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field.
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Abstract
An identification tag which can be encoded with multiple bits of information and can be remotely interrogated and read includes a plurality of magnetic elements. The information is stored in the magnetic elements which produce a large domain wall displacement (Barkhausen jump) at a particular magnetic field.
49 Citations
23 Claims
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1. A multibit identification tag for storing digital data, comprising:
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a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes; a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; and a hard magnetic layer deposited onto said first nonmagnetic spacer layer, a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and
a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer,wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field. - View Dependent Claims (5, 6)
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2. A multibit identification tag for storing digital data, comprising;
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a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes; a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
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3. A multibit identification tag for storing digital data, comprising:
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a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field, wherein each of said plurality of magnetic structures includes; a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein. - View Dependent Claims (4)
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7. A method of constructing a multibit identification tag for storing digital data, said method comprising steps of:
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depositing Barkhausen jump magnetic material onto a substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and depositing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising a plurality of magnetic structures, each of said plurality of magnetic structures producing a discontinuous change in magnetization at a different externally applied magnetic field and wherein each of said plurality of magnetic structures varies the effective magnetic field on each bit of said multibit tag, respectively, to allow said each bit to switch at a different applied magnetic field. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of constructing a multibit identification tag for storing digital dam, said method comprising the steps of:
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depositing Barkhausen jump magnetic material onto a first substrate; depositing a first nonmagnetic spacer layer on said Barkhausen jump magnetic material layer, said Barkhausen jump magnetic material layer being demagnetized and annealed; depositing a hard magnetic layer over said first nonmagnetic spacer layer; depositing a second nonmagnetic spacer layer on said hard magnetic layer; and providing a soft magnetic shunt path layer on said second nonmagnetic spacer layer, thereby to produce said multibit identification tag, said multibit identification tag comprising; a first substrate; an Barkhausen jump magnetic material deposited on said first substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer. - View Dependent Claims (20)
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21. An identification tag for storing multi-bit digital data, comprising:
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a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer.
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22. An identification tag for storing multi-bit digital data, comprising:
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a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein.
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23. An identification tag for storing multi-bit digital data, comprising:
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a substrate; an Barkhausen jump magnetic material deposited on said substrate; a first nonmagnetic spacer layer deposited on said Barkhausen jump magnetic material; a hard magnetic layer deposited onto said first nonmagnetic spacer layer; a second nonmagnetic spacer layer deposited onto said hard magnetic layer; and a soft magnetic shunt path layer deposited onto said second nonmagnetic spacer layer, wherein said soft magnetic shunt path layer includes at least one gap formed therein, said at least one gap incorporating nonmagnetic material therein.
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Specification