AU758991B2 - Magnetoresistive sensor element, especially angular sensor element - Google Patents

Magnetoresistive sensor element, especially angular sensor element Download PDF

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Publication number
AU758991B2
AU758991B2 AU41323/99A AU4132399A AU758991B2 AU 758991 B2 AU758991 B2 AU 758991B2 AU 41323/99 A AU41323/99 A AU 41323/99A AU 4132399 A AU4132399 A AU 4132399A AU 758991 B2 AU758991 B2 AU 758991B2
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AU
Australia
Prior art keywords
layer
sensor element
constructed
magnetoresistive sensor
magnetising
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Ceased
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AU41323/99A
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AU4132399A (en
Inventor
Martin Freitag
Franz Jost
Klaus Marx
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Robert Bosch GmbH
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Robert Bosch GmbH
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
    • G01D5/145—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices influenced by the relative movement between the Hall device and magnetic fields
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F10/00—Thin magnetic films, e.g. of one-domain structure
    • H01F10/32—Spin-exchange-coupled multilayers, e.g. nanostructured superlattices
    • H01F10/324—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer
    • H01F10/3268—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
    • H01F10/3281—Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn only by use of asymmetry of the magnetic film pair itself, i.e. so-called pseudospin valve [PSV] structure, e.g. NiFe/Cu/Co

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Power Engineering (AREA)
  • Measuring Magnetic Variables (AREA)
  • Hall/Mr Elements (AREA)
  • Thin Magnetic Films (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Transmission And Conversion Of Sensor Element Output (AREA)
  • Magnetic Heads (AREA)

Description

-1- Magnetoresistive sensor element, especially angular sensor element The present invention relates to a magnetoresistive sensor element, in particular an angle sensor element.
Sensors, in particular angle sensors, which operate on the basis of the magnetoresistive effect, are known. Here, the electric resistance of sensor elements dependent on the direction of an external magnetic field are measured. For example, systems have been described in which the so-called GMR (giant magnetoresistance) sensor elements, notably using self-stabilising magnetic layers, are employed (van den Berg et al., "GMR angle detector with an artificial antiferromagnetic subsystem", Journal ofMagnetism and Magnetic Materials 165 [1997] 524-528). Here, a first thin, so-called reference layer is produced in that between two opposite magnetised layers (for example of Co) an antiferromagnetic coupling layer (for example of Cu or Ru) is introduced. The magnetic stability of the reference layer is increased by approximately one order of magnitude over against individual Co layers. The magnetising direction of the reference layer (in the ideal case) does not depend on the direction of the external magnetic field (to be measured).
The reference layer is covered by a thin non-magnetic layer, on which in turn a soft magnetic layer, the so-called detection layer is constructed. The detection layer directs its magnetising (again in the ideal case), also in relatively small areas, in the direction of an external magnetic field. From the theory of the magnetoresistive effect, it is known that a sensor signal follows a function R(a) Ro AR*sin(a), Ro being a offset resistance, AR a signal sweep of the sensor and a the angle to be measured between an indicated sensor 25 direction (notably the reference device) and the direction of the external magnetic field.
A disadvantage of systems of this kind exists in that impreciseness or errors in determining angles can result from the various magnetic interactions or effects. Errors in angle are caused, for the most part, by two factors. One is that the magnetic reference is influenced by the magnetic field to be measured and does not remain rigid in the direction indicated, the other that the magnetising direction does not follow the detection layer without error or without lag in the direction of the external magnetic field.
30/01/03,ehl 1227.spc,l -2- The object of the invention is, then, the creation of a magnetoresistive sensor element or a sensor with which angle errors can be avoided or at least lessened.
According to the present invention there is provided a magnetoresistive sensor element, in particular an angle sensor element, with a first, magnetic layer, whose magnetising direction represents a reference direction, a second, non-magnetic layer constructed on the first layer and a third magnetic layer, whose magnetising direction can be influenced by an external magnetic field constructed on the second layer, whereby the third layer is constructed at least partially in the form of individual segments, wherein the segments are at least partially ellipsoid.
According to a further aspect of the present invention there is provided a magnetoresistive sensor element, in particular an angle sensor element, with a first, magnetic layer, whose magnetising direction represents a reference direction, a second, non-magnetic layer 15 constructed on the first layer and a third magnetic layer, whose magnetising direction can o S: be influenced by an external magnetic field, constructed on the second layer, whereby the third layer is constructed at least partially in the form of individual segments, wherein the first layer consists of a layer arrangement with a self-stabilising coupling according to the type of an artificial antiferromagnet.
According to yet a further aspect of the present invention there is provided a magnetoresistive sensor element, in particular an angle sensor element, with a first, .•magnetic layer, whose magnetising direction represents a reference direction, a second, non-magnetic layer constructed on the first layer and a third magnetic layer, whose 25 magnetising direction can be influenced by an external magnetic field constructed on the second layer, whereby the third layer is constructed at least partially in the form of oo individual segments, wherein the sensor element is constructed as a meander.
According to the invention, a sensor element is created with which the magnetising direction of the detection layer can follow an external magnetic field, in particular also a small external magnetic field considerably more easily and more precisely or with less lag than was possible with sensor elements. The improvement of the preciseness of the sensor element achievable by this means is achievable at low technical cost (for example st&.Wring of the detection layer by means of known chemical procedures).
30/01/03,ehl 1227 .spc,2 2a It is particularly preferred that the segments are constructed at least partially circular or ellipsis-shaped. With a shape of this kind one obtains a particularly lag-free and precise alignment of the magnetising direction of the detection layer with reference to an external magnetic field. Expediently, the sensor element has long or extended shape. By means of this construction, a large degree of independence of the reference magnetising from the external magnetic field is achieved. By means of the extended form or anisotropy of the sensor element (its length should be considerably greater 30/01/03,ehl 1227.spc,2 (k WOOO0/17666 PCT/DE99/01013 3 than its breadth) in particular a favourable effect on the self-stabilising of a reference layer constructed as artificial antiferromagnet is achievable.
A particular advantage lies in the meandering shape of the sensor elements. By this means, very long sensor structures are possible in a small area can be realised.
Advantageously, the first layer is a hard magnetic layer. Layers of this kind are economically realisable and guarantee a good magnetic stability of the reference layer.
The third layer is advantageously formed as a soft magnetic layer. Layers of this kind can be realised in a multiplicity of various shapes simply and economically. Ne-Fe alloys are named as a preferred example for soft magnetic materials.
It is preferred that the first layer consist of a layer arrangement with a self-stabilising coupling (artificial antiferromagnet). Layers of this type feature a particularly high magnetic stability, furthermore a long shaping of the sensor element have an especially favourable effect on the magnetic stability of layer arrangements of this type.
It is also preferred that the first layer have an artificially pinned or biased magnetising. A magnetising of this type is achievable, for example, by means of a magnetising device operating together with a charged conductor of the first layer for the stabilising of its magnetising direction.
It is preferred that the first and third layers are manufactured using GMR materials.
The invention will now be described in detail with the aid of a preferred embodiment with reference to the enclosed drawing. In it Figure 1 shows a schematic plan view of a preferred embodiment of the sensor element of the invention and Figure 2 shows the sensor element of Figure 1 schematically in a side view.
WOOO0/1 7666 PCT/DE99/01013 4 The sensor element depicted in Figure 1 features a first, magnetic or magnetised layer 1, which represents the reference layer. The internal construction of this first layer is not represented in detail. It is preferred that the first layer 1 be designed as an artificial artiferromagnetic substance, ie. a thin, metallic intermediate layer is constructed which operates as an antiferromagnetic coupling layer between two thin magnetic layers with (in basic condition) antiparallel magnetising. With reference to the prevailing magnetic conditions necessary for the creation of a self-stabilising artificial antiferromagnet, see the article by van den Berg et al referred to above.
The direction of the reference magnetising created by means of the first layer 1 is represented in Figure 1 and Figure 2 by means of an arrow 5. The direction of an external magnetic field to be measured is indicated by means of a broken line arrow.
A thin, nonmagnetic second layer 2 is applied to the first layer 1 onto which a magnetic third layer 3 (detection layer) is constructed.
The layer system with the layers 1, 2, 3 is advantageously manufactured in the schematically represented extended (or meandering) form, the third layer 3 being constructured initially unstructured, ie. corresponding to the layers 1, 2. Then the third layer 3 is selectively structured in the form of ellipses 3a depicted or in the form of circles for example by means of chemical procedures (eg. an etching process). A structuring of this kind proves to be appropriate for the sensor function as, by this means, the magnetising direction can follow small magnetic fields relatively easily.
The magnetising (corresponding to the direction 6 of the external magnetic field) is represented by means of arrows 7 for the respective ellipses 3a.
When a voltage is applied to the respective ends 10, 11 of the sensor element, a characteristic resistance value of the sensor element from which the angle of the magnetising direction of the external field can be determined results, dependent on an adjacent external magnetic field.
to WOOO/17666 PCT/DE99/01013 The sensor elements of the invention can, in the customary way be connected, for example, to bridge circuits in the usual way. Angle measurements are possible particularly simply and reliably with sensors which use this type of bridge circuit.
14.09.1998 ROBERT BOSCH GMBH, 70442 Stuttgart

Claims (11)

1. A magnetoresistive sensor element, in particular an angle sensor element, with a first, magnetic layer, whose magnetising direction represents a reference direction, a second, non-magnetic layer constructed on the first layer and a third magnetic layer, whose magnetising direction can be influenced by an external magnetic field constructed on the second layer, whereby the third layer is constructed at least partially in the form of individual segments, wherein the segments are at least partially ellipsoid.
2. The magnetoresistive sensor element as claimed in Claim 1, wherein said magnetoresistive element has a long form.
3. The magnetoresistive sensor element as claimed in Claim 1 or Claim 2, wherein said magnetoresistive element is formed in a meandering shape.
4. The magnetoresistive sensor element as claimed in any one of the preceding claims, wherein the first layer is a hard magnetic layer.
5. The magnetoresistive sensor element as claimed in any one of the preceding claims, wherein the third layer is a soft magnetic layer.
6. The magnetoresistive sensor element as claimed in any one of the preceding claims, wherein the first layer consists of a layer arrangement with a self-stabilizing coupling.
7. The magnetoresistive sensor element as claimed in any one of the preceding claims, wherein the first layer features an artificially pinned magnetising.
8. The magnetoresistive sensor element as claimed in any one of the preceding claims, wherein the first and/or third layer is/are manufactured using GMR materials.
9. A magnetoresistive sensor element, in particular an angle sensor element, with a first, magnetic layer, whose magnetising direction represents a reference direction, a a second, non-magnetic layer constructed on the first layer and a third magnetic layer, whose 30/01/03,ehl 1227.spc,6 magnetising direction can be influenced by an external magnetic field constructed on the second layer, whereby the third layer is constructed at least partially in the form of individual segments, wherein the first layer consists of a layer arrangement with a self- stabilising coupling according to the type of an artificial antiferromagnet.
A magnetoresistive sensor element, in particular an angle sensor element, with a first, magnetic layer, whose magnetising direction represents a reference direction, a second, non-magnetic layer constructed on the first layer and a third magnetic layer, whose magnetising direction can be influenced by an external magnetic field constructed on the second layer, whereby the third layer is constructed at least partially in the form of individual segments, wherein the sensor element is constructed as a meander.
11. A magnetoresistive sensor element, in particular an angle sensor element, substantially as hereinbefore described with reference to the accompanying drawings. ***Dated this 3 0 th day of January. 2003 ROBERT BOSCH GMBH By Their Patent Attorneys CALLINAN LAWRIE 9 ooooo* o *go• 30/01/03,chl 1227.spc, 7
AU41323/99A 1998-09-22 1999-04-03 Magnetoresistive sensor element, especially angular sensor element Ceased AU758991B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE1998143349 DE19843349A1 (en) 1998-09-22 1998-09-22 Magneto-resistive sensor element for measurement of external magnetic field angle, especially in bridge circuits, has outer sensor layer comprised partially or completely of individual segments
DE19843349 1998-09-22
PCT/DE1999/001013 WO2000017666A1 (en) 1998-09-22 1999-04-03 Magnetoresistive sensor element, especially angular sensor element

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AU4132399A AU4132399A (en) 2000-04-10
AU758991B2 true AU758991B2 (en) 2003-04-03

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EP (1) EP1046046A1 (en)
JP (1) JP2002525609A (en)
AU (1) AU758991B2 (en)
DE (1) DE19843349A1 (en)
WO (1) WO2000017666A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10255327A1 (en) * 2002-11-27 2004-06-24 Robert Bosch Gmbh Magnetoresistive sensor element and method for reducing the angular error of a magnetoresistive sensor element
JP5590349B2 (en) 2012-07-18 2014-09-17 Ｔｄｋ株式会社 Magnetic sensor system
US10096767B2 (en) * 2013-03-09 2018-10-09 Taiwan Semiconductor Manufacturing Company, Ltd. Elongated magnetoresistive tunnel junction structure

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0622781A2 (en) * 1993-04-30 1994-11-02 International Business Machines Corporation Granular multilayer magnetoresistive sensor
EP0660127A2 (en) * 1993-12-23 1995-06-28 International Business Machines Corporation Multilayer magnetoresistive sensor
EP0730162A2 (en) * 1995-03-02 1996-09-04 Siemens Aktiengesellschaft Sensor apparatus with magnetoresistif sensorelement in a bridge circuit

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3886589B2 (en) * 1997-03-07 2007-02-28 アルプス電気株式会社 Giant magnetoresistive element sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0622781A2 (en) * 1993-04-30 1994-11-02 International Business Machines Corporation Granular multilayer magnetoresistive sensor
EP0660127A2 (en) * 1993-12-23 1995-06-28 International Business Machines Corporation Multilayer magnetoresistive sensor
EP0730162A2 (en) * 1995-03-02 1996-09-04 Siemens Aktiengesellschaft Sensor apparatus with magnetoresistif sensorelement in a bridge circuit

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JP2002525609A (en) 2002-08-13
DE19843349A1 (en) 2000-03-23
WO2000017666A1 (en) 2000-03-30
EP1046046A1 (en) 2000-10-25
AU4132399A (en) 2000-04-10

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