US4992659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Near-field lorentz force microscopy
Assignee: International Business Machines Corp
•
Filing: 1989-07-27
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Granted: 1991-02-12
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Expires: 2009-07-27
Abstract
Abstract Magnetic structures of a sample are imaged by measuring Lorentz force-induced deflection of the tip of a scanning tunneling microscope. While scanning the sample, an a.c. voltage signal at a first predetermined frequency equal to the resonance frequency of the tip is applied to the tip for generating a current between the tip and the surface of the sample for causing the tip to undergo vibratory motion relative to the sample. The tip motion, indicative of the presence of a magnetic field, is optically detected. In an alternative embodiment for providing improved resolution the tip is made to undergo motion at a second predetermined frequency in a direction parallel to the longitudinal axis of the tip and normal to the surface of the sample. The tip motion is optically detected at the sum or difference frequency of the first and second predetermined frequencies for providing improved lateral resolution of the magnetic field measurements using a scanning tunneling microscope. In the alternative embodiment the sum or difference frequency, which ever is detected, is made equal to the resonance frequency of the tip. The magnetic field measurement and tip position are provided to a computer which, in turn, provides an output signal to a device for providing a graphical representation of the magnetic field at different positions on the surface of the sample.
Inventors
- 👤 David W. Abraham
- 👤 Hemantha K. Wickramasinghe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:42
CPC Classifications
G; G01; G01Q; G01Q20/00; G01Q20/02; G01N; G01N27/00; G01N27/72; G01N27/82; G01Q60/00; G01Q60/10; G01Q60/16; Y; Y10; Y10S; Y10S977/00; Y10S977/84; Y10S977/849; Y10S977/852; Y10S977/86; Y10S977/865
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
175 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to said tip for providing a current signal at a frequency substantially equal to the resonance frequency of said tip for generating a current between said tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 2
Independent Claim
175 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to said tip for providing a current signal at a frequency substantially equal to the resonance frequency of said tip for generating a current between said tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 3
Dependent Claim
33 words
An apparatus as set forth in claim 1 further comprising output device means coupled to said computer means for providing an image of the magnetic field magnitude at corresponding positions of the tip.
Claim 4
Dependent Claim
16 words
An apparatus as set forth in claim 2, wherein said output device means comprises a screen.
Claim 5
Dependent Claim
16 words
An apparatus as set forth in claim 2, wherein said output device means comprises a plotter.
Claim 6
Dependent Claim
24 words
An apparatus as set forth in claim 1, wherein said drive means comprises piezoelectric drive means for positioning the tip relative to the surface.
Claim 7
Dependent Claim
21 words
An apparatus as set forth in claim 5, wherein said piezoelectric drive means positions the tip relative to a stationary surface.
Claim 8
Dependent Claim
21 words
An apparatus as set forth in claim 5, wherein said piezoelectric drive means position the surface relative to a stationary tip.
Claim 9
Dependent Claim
25 words
An apparatus as set forth in claim 1, wherein said computer means provides another output indicative of the topography of the surface of the sample.
Claim 10
Dependent Claim
17 words
An apparatus as set forth in claim 1, wherein said detector means is an optical heterodyned interferometer.
Claim 11
Independent Claim
126 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a current signal at a frequency substantially equal to the resonance frequency of the tip for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 12
Independent Claim
126 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a current signal at a frequency substantially equal to the resonance frequency of the tip for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 13
Dependent Claim
29 words
A method as set forth in claim 10, further comprising the step of displaying the position of the tip and the magnetic field magnitude corresponding to the tip position.
Claim 14
Dependent Claim
23 words
A method as set forth in claim 10, further comprising the step of simultaneously measuring the topography of the surface of the sample.
Claim 15
Dependent Claim
23 words
A method as set forth in claim 12, further comprising the step of simultaneously displaying the topography of the surface of the sample.
Claim 16
Dependent Claim
18 words
A method as set forth in claim 10, wherein said measuring the motion is optically measuring the motion.
Claim 17
Independent Claim
187 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: piezoelectric drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and providing a signal indicative of the position of the tip; generator means for providing a current at a frequency substantially equal to the resonance frequency of the tip for generating a current signal between the tip and the surface of the sample for causing the tip to undergo vibratory motion in the presence of a magnetic field; optical heterodyned interferometric means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion; computer means coupled to said optical heterodyned interferometric means and said piezoelectric drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position, and output device means for providing a display responsive to said output signal.
Claim 18
Independent Claim
187 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: piezoelectric drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and providing a signal indicative of the position of the tip; generator means for providing a current at a frequency substantially equal to the resonance frequency of the tip for generating a current signal between the tip and the surface of the sample for causing the tip to undergo vibratory motion in the presence of a magnetic field; optical heterodyned interferometric means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion; computer means coupled to said optical heterodyned interferometric means and said piezoelectric drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position, and output device means for providing a display responsive to said output signal.
Claim 19
Dependent Claim
25 words
An apparatus as set forth in claim 15 said computer means providing another output signal indicative of the topography of the surface of the sample.
Claim 20
Independent Claim
205 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to the tip for providing a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; means coupled to said drive means for causing the tip to undergo vibratory motion relative to the surface at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 21
Independent Claim
205 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to the tip for providing a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; means coupled to said drive means for causing the tip to undergo vibratory motion relative to the surface at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 22
Dependent Claim
33 words
An apparatus as set forth in claim 17 further comprising output device means coupled to said computer means for providing an image of the magnetic field magnitude at corresponding positions of the tip.
Claim 23
Dependent Claim
16 words
An apparatus as set forth in claim 18, wherein said output device means comprises a screen.
Claim 24
Dependent Claim
16 words
An apparatus as set forth in claim 18, wherein said output device means comprises a plotter.
Claim 25
Dependent Claim
24 words
An apparatus as set forth in claim 17, wherein said drive means comprises piezoelectric drive means for positioning the tip relative to the surface.
Claim 26
Dependent Claim
21 words
An apparatus as set forth in claim 21, wherein said piezoelectric drive means positions the tip relative to a stationary surface.
Claim 27
Dependent Claim
21 words
An apparatus as set forth in claim 21, wherein said piezoelectric drive means position the surface relative to a stationary tip.
Claim 28
Dependent Claim
18 words
An apparatus as set forth in claim 17, wherein said detector means is an optical heterodyned interferometer means.
Claim 29
Dependent Claim
51 words
An apparatus as set forth in claim 17, wherein said detector means measures the motion of the tip at a sum frequency substantially equal to the sum of said first predetermined frequency and said second predetermined frequency and the sum frequency is substantially equal to the resonance frequency of the tip.
Claim 30
Dependent Claim
18 words
An apparatus as set forth in claim 25 wherein said detector means is an optical heterodyned interferometer means.
Claim 31
Dependent Claim
51 words
An apparatus as set forth in claim 17, wherein said detector means measures the motion of the tip at a difference frequency substantially equal to the difference of said first predetermined frequency and said second predetermined frequency and the difference frequency is substantially equal to the resonance frequency of the tip.
Claim 32
Dependent Claim
18 words
An apparatus as set forth in claim 27 wherein said detector means is an optical heterodyned interferometer means.
Claim 33
Dependent Claim
25 words
An apparatus as set forth in claim 17, wherein said computer means provides another output indicative of the topography of the surface of the sample.
Claim 34
Independent Claim
142 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; simultaneously vibrating the tip at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 35
Independent Claim
142 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of a magnetic field; simultaneously vibrating the tip at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 36
Dependent Claim
29 words
A method as set forth in claim 30 further comprising the step of displaying the position of the tip and the magnetic field magnitude corresponding to the tip position.
Claim 37
Dependent Claim
23 words
A method as set forth in claim 30, further comprising the step of simultaneously measuring the topography of the surface of the sample.
Claim 38
Dependent Claim
23 words
A method as set forth in claim 32, further comprising the step of simultaneously displaying the topography of the surface of the sample.
Claim 39
Dependent Claim
14 words
A method as set forth in claim 32 wherein said measuring is optical measuring.
Claim 40
Dependent Claim
50 words
A method as set forth in claim 30 wherein said measuring measures the motion of the tip at a sum frequency substantially equal to the sum of said first predetermined frequency and said second predetermined frequency and the sum frequency is substantially equal to the resonance frequency of the tip.
Claim 41
Dependent Claim
14 words
A method as set forth in claim 35 wherein said measuring is optical measuring.
Claim 42
Dependent Claim
50 words
A method as set forth in claim 30 wherein said measuring measures the motion of the tip at a difference frequency substantially equal to the difference between said first predetermined frequency and said second predetermined frequency and the difference frequency is substantially equal to the resonance frequency of the tip.
Claim 43
Dependent Claim
14 words
A method as set forth in claim 37 wherein said measuring is optical measuring.
Claim 44
Independent Claim
215 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: piezoelectric drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and providing a signal indicative of the position of the tip; generator means coupled to the tip for providing a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of the magnetic field; means coupled to said piezoelectric drive means for causing the tip to undergo vibratory motion at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; optical heterodyned interferometric means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion; computer means coupled to said optical heterodyned interferometric means and said piezoelectric drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position, and output drive means for providing a display responsive to said output signal.
Claim 45
Independent Claim
215 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: piezoelectric drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and providing a signal indicative of the position of the tip; generator means coupled to the tip for providing a current signal at a first predetermined frequency for generating a current between the tip and the surface for causing the tip to undergo vibratory motion in the presence of the magnetic field; means coupled to said piezoelectric drive means for causing the tip to undergo vibratory motion at a second predetermined frequency along an axis substantially normal to the plane of the surface of the sample; optical heterodyned interferometric means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface of the sample and providing a signal indicative of such motion; computer means coupled to said optical heterodyned interferometric means and said piezoelectric drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position, and output drive means for providing a display responsive to said output signal.
Claim 46
Dependent Claim
25 words
An apparatus as set forth in claim 39 said computer means providing another output signal indicative of the topography of the surface of the sample.
Claim 47
Dependent Claim
53 words
An apparatus as set forth in claim 39 wherein said optical heterodyned interferometric means measures the motion of the tip at a sum frequency substantially equal to the sum of said first predetermined frequency and said second predetermined frequency and said sum frequency is substantially equal to the resonance frequency of the tip.
Claim 48
Dependent Claim
52 words
An apparatus as set forth in claim 39 wherein said optical heterodyne means measures the motion of the tip at a difference frequency substantially equal to the difference between said first predetermined frequency and said second predetermined frequency and said difference frequency is substantially equal to the resonance frequency of the tip.
Claim 49
Independent Claim
144 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to said tip for providing a signal for generating a current between said tip and the surface; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 50
Independent Claim
144 words
An apparatus for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising: drive means for controlling the distance between the tip and a surface of the sample and a position of the tip for enabling scanning of the surface and for providing a signal indicative of the position of the tip relative to the sample; generator means coupled to said tip for providing a signal for generating a current between said tip and the surface; detector means disposed for measuring the motion of the tip in a direction substantially parallel to the plane of the surface and providing a signal indicative of such motion, and computer means coupled to said detector means and said drive means for providing an output signal indicative of a position of the tip and a magnetic field magnitude corresponding to the position.
Claim 51
Dependent Claim
33 words
An apparatus as set forth in claim 43 further comprising output device means coupled to said computer means for providing an image of the magnetic field magnitude at corresponding positions of the tip.
Claim 52
Dependent Claim
25 words
An apparatus as set forth in claim 43, wherein said computer means provides another output indicative of the topography of the surface of the sample.
Claim 53
Dependent Claim
17 words
An apparatus as set forth in claim 43, wherein said detector means is an optical heterodyned interferometer.
Claim 54
Independent Claim
95 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a signal for generating a current between the tip and the surface; measuring the motion of the tip in a direction substantially parallel to the plane of the surface and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 55
Independent Claim
95 words
A method for measuring a magnetic field in a sample using a scanning tunneling microscope having a tip comprising the steps of: disposing the tip in close proximity to a surface of a sample and scanning the surface; providing to the tip a signal for generating a current between the tip and the surface; measuring the motion of the tip in a direction substantially parallel to the plane of the surface and providing a signal indicative of such motion, and computing the position of the tip and a magnetic field magnitude corresponding to the position.
Claim 56
Dependent Claim
29 words
A method as set forth in claim 47, further comprising the step of displaying the position of the tip and the magnetic field magnitude corresponding to the tip position.
Claim 57
Dependent Claim
23 words
A method as set forth in claim 47, further comprising the step of simultaneously measuring the topography of the surface of the sample.
Claim 58
Dependent Claim
23 words
A method as set forth in claim 49, further comprising the step of simultaneously displaying the topography of the surface of the sample.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |