WO1997046892A3 - Magnetoresistance sensor having minimal hysteresis problems - Google Patents

Magnetoresistance sensor having minimal hysteresis problems Download PDF

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Publication number
WO1997046892A3
WO1997046892A3 PCT/US1997/009658 US9709658W WO9746892A3 WO 1997046892 A3 WO1997046892 A3 WO 1997046892A3 US 9709658 W US9709658 W US 9709658W WO 9746892 A3 WO9746892 A3 WO 9746892A3
Authority
WO
WIPO (PCT)
Prior art keywords
field
excitation
magnetization
magnetic
versus
Prior art date
Application number
PCT/US1997/009658
Other languages
French (fr)
Other versions
WO1997046892A2 (en
Inventor
E Dan Dahlberg
Timothy J Moran
Original Assignee
Univ Minnesota
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US08/655,222 external-priority patent/US5747997A/en
Priority claimed from US08/739,632 external-priority patent/US6166539A/en
Application filed by Univ Minnesota filed Critical Univ Minnesota
Publication of WO1997046892A2 publication Critical patent/WO1997046892A2/en
Publication of WO1997046892A3 publication Critical patent/WO1997046892A3/en

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Classifications

    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C17/00—Compasses; Devices for ascertaining true or magnetic north for navigation or surveying purposes
    • G01C17/02—Magnetic compasses
    • G01C17/28—Electromagnetic compasses
    • G01C17/30—Earth-inductor compasses
    • 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
    • G01R33/04—Measuring direction or magnitude of magnetic fields or magnetic flux using the flux-gate principle
    • 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
    • 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
    • G01R33/096—Magnetoresistive devices anisotropic magnetoresistance sensors
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/3906—Details related to the use of magnetic thin film layers or to their effects
    • G11B5/3929—Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding
    • G11B5/3932—Magnetic biasing films
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
    • G11B5/399—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures with intrinsic biasing, e.g. provided by equipotential strips
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/465—Arrangements for demagnetisation of heads
    • 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
    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H10N50/85—Magnetic active materials
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B2005/0002—Special dispositions or recording techniques
    • G11B2005/0005—Arrangements, methods or circuits
    • G11B2005/001—Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure
    • G11B2005/0013—Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure of transducers, e.g. linearisation, equalisation
    • G11B2005/0016—Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure of transducers, e.g. linearisation, equalisation of magnetoresistive transducers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
    • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
    • G11B2005/3996—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/012—Recording on, or reproducing or erasing from, magnetic disks

Abstract

The present invention provides a method and apparatus for utilizing magnetoresistance devices for the measurement of weak magnetic fields. An oscillating excitation magnetic field is applied to a magnetoresistive (MR) sensing element such that the MR element is driven into one or both of two antiparallel saturation states. The amplitude of the excitation field is large enough to reverse the magnetization of the soft layer during each cycle. In one embodiment, the MR element is provided with a current, and a voltage proportional to the resistance is measured. Components of the voltage signal at multiples of the excitation frequency are then proportional to the environmental magnetic field. In one embodiment, an MR element having a resistance-versus-field transfer function that is symmetric (e.g., an anisotropic MR element) is used; while in another embodiment, an MR element having a resistance-versus-field transfer function that is asymmetric (e.g., a spin-valve MR element) is used. Various apparatus and methods for measuring the amount of time spent in one or both saturated states versus the unsaturated or transition states are described. In one embodiment, the magentic excitation field is generated using a current strip deposited onto the top of the other device layers, so that the entire device can be produced on a single chip. In one embodiment, a 'flexible' magnetoresistive structure includes a 'flexible' ferromagnetic layer having a hard-magnetization-portion layer, and a soft-magnetization-portion layer, thus providing a smooth magnetic transition when this bilayer switches. One embodiment includes s supporting data-read head structure that positions the flexible magnetoresistive (MR) sensing element to sense a magnetic field in a data storage device such as a magnetic-disk drive.
PCT/US1997/009658 1996-06-05 1997-06-05 Magnetoresistance sensor having minimal hysteresis problems WO1997046892A2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US08/655,222 US5747997A (en) 1996-06-05 1996-06-05 Spin-valve magnetoresistance sensor having minimal hysteresis problems
US08/655,222 1996-06-05
US08/739,632 US6166539A (en) 1996-10-30 1996-10-30 Magnetoresistance sensor having minimal hysteresis problems
US08/739,632 1996-10-30

Publications (2)

Publication Number Publication Date
WO1997046892A2 WO1997046892A2 (en) 1997-12-11
WO1997046892A3 true WO1997046892A3 (en) 1998-04-09

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/009658 WO1997046892A2 (en) 1996-06-05 1997-06-05 Magnetoresistance sensor having minimal hysteresis problems

Country Status (1)

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WO (1) WO1997046892A2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0989411A3 (en) * 1998-09-25 2004-10-06 Alps Electric Co., Ltd. Magneto-impedance effect element
JP2006266909A (en) * 2005-03-24 2006-10-05 Alps Electric Co Ltd Magnetic detector, and electronic azimuth meter using the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1063037A (en) * 1963-05-10 1967-03-22 Siemens Ag The measurement of magnetic fields
US4259703A (en) * 1978-06-20 1981-03-31 Emi Limited Magneto resistive magnetic transducers
GB2064140A (en) * 1979-11-27 1981-06-10 Landis & Gyr Ag Measuring transducers for measuring magnetic fields
EP0074219A1 (en) * 1981-09-09 1983-03-16 EMI Limited Arrangements for resolving magnetic field components
US5255442A (en) * 1991-12-20 1993-10-26 Donnelly Corporation Vehicle compass with electronic sensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1063037A (en) * 1963-05-10 1967-03-22 Siemens Ag The measurement of magnetic fields
US4259703A (en) * 1978-06-20 1981-03-31 Emi Limited Magneto resistive magnetic transducers
GB2064140A (en) * 1979-11-27 1981-06-10 Landis & Gyr Ag Measuring transducers for measuring magnetic fields
EP0074219A1 (en) * 1981-09-09 1983-03-16 EMI Limited Arrangements for resolving magnetic field components
US5255442A (en) * 1991-12-20 1993-10-26 Donnelly Corporation Vehicle compass with electronic sensor

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
FLYNN D: "DEMODULATION OF A MAGNETORESISTIVE SENSOR SIGNAL TO ACHIEVE A LOW-COST, STABLE AND HIGH-RESOLUTION VECTOR MAGNETOMETER", SENSORS AND ACTUATORS A, vol. 50, no. 3, 1 September 1995 (1995-09-01), pages 187 - 190, XP000584889 *
SPONG J K ET AL: "GIANT MAGNETORESISTIVE SPIN VALVE BRIDGE SENSOR", IEEE TRANSACTIONS ON MAGNETICS, vol. 32, no. 2, 1 March 1996 (1996-03-01), pages 366 - 371, XP000555504 *
T.J.MORAN ET AL.: "Magnetoresistive sensor for weak magnetic fields", APPL. PHYS. LETT., vol. 70, no. 14, 7 April 1997 (1997-04-07), US, pages 1894 - 1896, XP000689524 *

Also Published As

Publication number Publication date
WO1997046892A2 (en) 1997-12-11

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