# US 5,708,407 A · Current sensor comprising a magnetoresistive tape and its production process

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- Number: US 5,708,407 A
- Document ID: US5708407A
- Status: Granted
- Kind: A
- Application number: 08/619,640
- Filed: 1996-08-23
- Granted: 1998-01-13
- Earliest claimed: 1993-09-27
- Assignees: Commissariat a l'Energie Atomique
- Inventors: Jean Mouchot; Jean-Marc Fedeli; Franck Boileau; Patrick Mas
- Web page: https://patentgrep.com/patent/US5708407A

## CPC

- G01R 15/205: {using magneto-resistance devices, e.g. field plates}
- B82Y 25/00: Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
- G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)}
- H10N 50/10: Magnetoresistive devices
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

The invention relates to a current sensor or transducer (10) for measuring the current flowing through an electric conductor (11), comprising a magnetoresistive tape (12) surrounding the conductor and whose ends (13, 14) are to be connected to a device for measuring said current, characterized in that the tape (12) is shaped like a tube with an axis centred on the conductor and in that it is formed with a multilayer, metallic, magnetic structure, whose layers constitute the same number of stacked elementary tubes concentric to said axis.

## Claims

### Claim 1

Current sensor or transducer for measuring the current flowing through an electric conductor, comprising a magnetoresistive tape surrounding the conductor and whose ends are to be connected to a device for measuring said current, in which the tape is shaped like a tube with an axis centered on the conductor and that it is formed with a multilayer, metallic, magnetic structure, whose layers constitute the same number of stacked elementary tubes concentric to said axis.

### Claim 2 (depends on 1)

Current sensor according to claim 1, wherein the tape has means for the magnetic polarization of the metallic, multilayer, magnetic structure.

### Claim 3 (depends on 2)

Current sensor according to claim 2, wherein the tape has a sequence of metallic, multilayer, magnetic structure elements, two successive elements of the sequence being electrically interconnected by magnetic, conductive elements constituting said magnetic polarization means.

### Claim 4 (depends on 2)

Current sensor according to claim 2, wherein the tape has a sequence of metallic, multilayer, magnetic structure elements, two successive elements of the sequence being electrically interconnected by conductive elements supporting magnetic elements constituting the said magnetic polarization means.

### Claim 5 (depends on 4)

Current sensor according to claim 4, wherein, in order to reduce the resistance of the magnetoresistive tape due to the conductive elements, the section of said conductive elements, considered in a plane perpendicular to the tape length, exceeds the section, also considered in a plane perpendicular to the tape length, of metallic, multilayer, magnetic structure elements.

### Claim 6 (depends on 2)

Current sensor according to claim 2, wherein said magnetic polarization means are produced from a hard, magnetic material.

### Claim 7 (depends on 1)

Current sensor according to claim 1, wherein it is constituted by a circular support, to which is fixed the magnetoresistive tape.

### Claim 8

Process for the production of a current sensor incorporating a magnetoresistive tape having ends for connection to a device for measuring the current, comprising the following stages:
deposition on one face of an insulating substrate of a conductive, metallic layer,
etching the conductive, metallic layer to form the ends of the tape,
deposition of a conductive, magnetic material layer on said face,
etching said conductive, magnetic material layer to obtain a sequence of aligned, separated, conductive, magnetic elements located between said ends,
deposition on said face of a metallic, multilayer, magnetic structure layer,
etching said metallic, multilayer, magnetic structure layer to obtain elements solely between the magnetic elements and so as to ensure the electrical continuity between said ends.

### Claim 9

Process for the production of a current sensor incorporating a magnetoresistive tape having ends to be connected to a device for measuring the current, comprising the following stages:
deposition on one face of an insulating substrate a conductive, metallic layer,
etching the conductive, metallic layer to form the ends of the tape and a sequence of aligned, separated, conductive elements between said ends,
deposition of a magnetic material layer on said face,
etching said magnetic material layer to obtain a sequence of magnetic elements resting on the conductive elements,
deposition on said face of a metallic, multilayer, magnetic structure layer,
etching said metallic, multilayer, magnetic structure layer to obtain elements solely between the conductive elements and to ensure the electrical continuity between said ends.

### Claim 10 (depends on 8, 9)

Process according to either of the claims 8 and 9, wherein the insulating substrate used can be deformed.