EP1425595A1 - Microscope squid a balayage a resolution spatiale amelioree - Google Patents

Microscope squid a balayage a resolution spatiale amelioree

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Publication number
EP1425595A1
EP1425595A1 EP01975166A EP01975166A EP1425595A1 EP 1425595 A1 EP1425595 A1 EP 1425595A1 EP 01975166 A EP01975166 A EP 01975166A EP 01975166 A EP01975166 A EP 01975166A EP 1425595 A1 EP1425595 A1 EP 1425595A1
Authority
EP
European Patent Office
Prior art keywords
squid
scanning
squid sensor
microscope
sensor
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP01975166A
Other languages
German (de)
English (en)
Other versions
EP1425595A4 (fr
Inventor
Fred Wellstood
Sojiphong Department of Physics CHATRAPHORN
Erin Fleet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Maryland at Baltimore
University of Maryland at College Park
Original Assignee
University of Maryland at Baltimore
University of Maryland at College Park
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
Application filed by University of Maryland at Baltimore, University of Maryland at College Park filed Critical University of Maryland at Baltimore
Publication of EP1425595A1 publication Critical patent/EP1425595A1/fr
Publication of EP1425595A4 publication Critical patent/EP1425595A4/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • G01R33/035—Measuring direction or magnitude of magnetic fields or magnetic flux using superconductive devices
    • G01R33/0354—SQUIDS
    • G01R33/0358—SQUIDS coupling the flux to the SQUID
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
    • G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
    • G01Q60/50—MFM [Magnetic Force Microscopy] or apparatus therefor, e.g. MFM probes
    • G01Q60/54—Probes, their manufacture, or their related instrumentation, e.g. holders
    • 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
    • G01R33/038—Measuring direction or magnitude of magnetic fields or magnetic flux using permanent magnets, e.g. balances, torsion devices
    • G01R33/0385—Measuring direction or magnitude of magnetic fields or magnetic flux using permanent magnets, e.g. balances, torsion devices in relation with magnetic force measurements

Definitions

  • the present invention is directed to a magnetic scanning device such as a scanning SQUID (Superconducting Quantum Interference Device) microscope; and more particularly to an apparatus and technique for improving the spatial resolution of the scanning SQUID microscope.
  • a magnetic scanning device such as a scanning SQUID (Superconducting Quantum Interference Device) microscope
  • the present invention relates to a scanning SQUID microscope for acquiring spatially resolved images of physical properties of an object where a SQUID sensor is positioned substantially perpendicular to a test surface of the object under investigation and where the SQUID sensor detects a tangential component of the magnetic field generated by the object.
  • the spatial resolution of the SQUID microscope is not limited to the area of the SQUID sensor.
  • Prior magnetic imaging devices using SQUIDS have maintained spatial resolution on the scale of a millimeter or larger which is too large for microscopically resolving images needed in semiconductors/micro-electronics testing. Additionally, these devices also required placing samples in a vacuum. Some samples such as liquids or biological specimens cannot tolerate vacuum, thus it is not practical to measure sources of biomagnetism which are currently the focus of much of the existing low spatial resolution SQUID imaging.
  • U.S. Patent #5,491,411 discloses methods and apparatus for imaging microscopic spatial variations in small currents and magnetic fields capable of providing measurements of magnetic fields with enhanced spatial resolution and magnetic field sensitivity.
  • the device requires placing a sample within a dewar which may result in the unwanted destruction of the sample when it is exposed to cryogenic liquid or a vacuum.
  • Arguendo even if the sample is able to tolerate the vacuum environment or cryogenic medium, introducing the sample into the vacuum or cryogenic space for imaging is a somewhat cumbersome and time consuming task.
  • the problem was at least partially resolved by the apparatus for microscopic imaging of electrical and magnetic properties of a sample disclosed in U.S. Patent #5,894,220.
  • the device includes a housing having a first portion containing a cryogenic medium and a second portion enveloping a vacuum space.
  • the cryogenic SQUID sensor is disposed within the vacuum space and in fluid communication with the cryogenic medium in the housing for heat exchange therewith.
  • the sample for measurement is positioned outside of the housing, at room temperature or higher, and can be "seen” by the SQUID sensor through a thin window made in the wall of the housing.
  • the output of the cryogenic SQUID sensor is monitored as it is scanned over the surface of the sample.
  • the SQUID sensor loop is oriented to be in a plane parallel to the sample plane so that only the normal component B z of the detected magnetic field is measured.
  • SQUID chip 10 secured to the lowermost point of a sapphire tip 12 (attached to a tube 18) is disposed in parallel with the plane of a sample 14. As the sample 14 moves in perpendicular directions X and Y, the SQUID sensor detects the magnetic field generated by the sample 14.
  • a magnetic field B is generated by a current path 16, extending in this particular example along the axis Y.
  • the problem associated with this technique results from the fact that each acquired data point is the magnetic field averaged over the area of the SQUID sensor projection on the direction of a scan. Since, as shown in Figure 3, the whole area of the SQUID sensor 10 faces (downwardly) toward the sample, and the projection area of the SQUID sensor onto the sample plane is large, the spatial resolution is then limited to the size of the SQUID sensor projecting onto the sample plane.
  • SQUID bias and readout wires 22 are coupled between the SQUID chip 10 and the processing equipment 24. It is clear to those skilled in the art, that, as shown in FIG. 1, the contact between the wires 22 and the SQUID chip 10 is difficult to fabricate. Additionally, due to limitations applied to the size of the SQUID chip, the contact resistance to the device can be undesirably high if the contact pages are made too small.
  • SQUID chip for accommodating modulation and feedback lines, as well as enlarged contact pads positioned thereon.
  • the SQUID chip may be fabricated with dimensions which permit patterning the modulation and feedback line on the same chip with the SQUID sensor in the same technological process and also permits a convenient and low resistance coupling of the bias/read-out wires to the SQUID chip.
  • a scanning SQUID microscope for acquiring spatially resolved images of physical properties of an object takes advantage of a SQUID sensor oriented substantially perpendicular to the plane of the object under investigation.
  • the SQUID sensor is patterned on a substrate, the plane of which is positioned in mutual perpendicular relationship with the surface under test containing the object.
  • the projection area of the SQUID sensor onto the object plane is negligible, and the averaging of the detected signals over the area of the sensor in the scanning direction is negligibly small compared to conventional scanning SQUID microscopes where the whole area of the SQUID sensor faces in a downward orientation to the object under investigation.
  • the scanning SQUID microscope further includes a position interpreting unit for outputting a signal corresponding to a position where magnetic field readings are made.
  • Imaging means are included which receive the signal from the position interpreting unit as well as the signal from the SQUID sensor corresponding to the tangential component of the magnetic field detected from which the imaging means further derive the spatially resolved images of the physical properties of the object.
  • the SQUID sensor is preferably formed of superconducting YBajCugO, patterned on the substrate made of SrTi0 3 bicrystal, although other suitable materials known to those skilled in the art are also applicable.
  • the SQUID sensor is attached to a cold-finger tip of the microscope and in particular to a flat or planar area extending at the end of the tip perpendicular relationship to the surface of the object under investigation.
  • the tip is preferably made of sapphire, although other thermally conducting non-magnetic materials may be used.
  • the scanning SQUID microscope includes a housing which has a first section containing a cryogenic medium and a second section enveloping a vacuum space.
  • a transparent window is formed in the second section of the housing for separating the vacuum space from the ambient atmosphere surrounding the housing.
  • the cold-finger tip with the SQUID sensor attached thereto is positioned within the vacuum space, while the object under investigation is positioned in ambient surroundings and is separated from the SQUID sensor by the transparent window.
  • a conduit extends between the first section of the housing and the sapphire tip to deliver the cryogenic medium to the sapphire tip for heat exchange with the SQUID sensor.
  • Means are provided in the scanning SQUID microscope for adjusting the relative disposition between the transparent window and the SQUID sensor as well as the distance between the SQUID sensor and the object under investigation.
  • the object under investigation is positioned on a scanning stage capable of moving in horizontal X and Y directions mutually perpendicular each to the other, and in the Z direction perpendicular to both the X and Y directions.
  • the size of the SQUID chip may be enlarged to permit larger contact areas for the wires coupling the SQUID chip to the processing means thus reducing the contact resistance to the SQUID. Additionally, due to the specific disposition of the SQUID chip at the sapphire tip, it is much easier to connect the wires to the SQUID chip than known in the prior art.
  • Figure 1 is a schematic representation of a Z-SQUID microscope of the prior art
  • Figure 2 is a schematic representation of the Z-SQUID sensor of the prior art oriented in parallel with regard to the scanning plane of an object under investigation;
  • Figure 3 is a diagrammatical representation of the magnetic field detected by the SQUID sensor of the prior art averaged over the area of the Z-SQUID in the direction of a scan;
  • Figure 4 shows a longitudinal section of the scanning SQUID microscope of the present invention
  • Figure 5 is a schematic representation of the cold-finger sapphire tip of the scanning SQUID microscope of the present invention with the SQUID sensor attached thereto;
  • Figure 6 shows schematically the relative disposition between the plane of the SQUID sensor of the present invention to the object under investigation;
  • Figure 7 is a diagrammatical representation of the detected magnetic field averaged over the area of the SQUID sensor projected onto the direction of a scan;
  • Figure 8 is a planar view of the surface of the SQUID chip on which the
  • SQUID sensor and modulation/feedback line are patterned in the same technological process.
  • Figure 9 is a diagram presenting comparison between the spatial resolutions of the scanning SQUID microscope of the prior art and of the present invention.
  • a scanning SQUID microscope 30 of the present invention includes a housing 32 which accommodates a cryogen containing portion 34 for receiving and holding liquid nitrogen 36, or any other cryogenic medium, as well as a vacuum space 38 which thermally insulates the cryogen containing portion 34 from room temperature.
  • the housing 32 thus is a modified dewar assembly having the vacuum space 38 maintained at about 10 "5 Torr.
  • the housing 32 includes an annular plate 40 having a circular opening 42 located substantially in the center thereof.
  • a window support 44 Spaced from the annular plate 40, is a window support 44 which supports a plastic flange 46 to the end of which a sapphire window support 48 is secured having an annular opening in which a transparent and thin window 50 is attached.
  • the window 50 is preferably formed of sapphire and is approximately 25 microns thick.
  • the annular plate 40 is connected via three threaded rods 52 (only two of which are shown in FIG. 4) to a horizontal adjustment annular disk 54 to allow movement of the window 50 with respect to SQUID sensor 56.
  • the adjustment screws 58 protrude through sides of the annular disk 54 to permit the movement of the window support 44 with respect to the annular disk 54 for alignment with the window 50 with respect to the SQUID sensor 56.
  • a flexible bellows tube 60 for delivery cryogen extends centrally and longitudinally within the housing 32 and includes stainless steel bellows 62, copper or brass tube 64, and a thermally conducting rod preferably forming a sapphire tip 66.
  • the stainless steel bellows 62 is in open communication at the end 68 with the cryogen containing portion 34 of the housing 32.
  • the end 70 of the bellows 62 is located in the vacuum space 38 and is mounted on the top of interior flange of a grommet 72.
  • the end 74 of the tube 64 is seated and soldered on the bottom of the interior flange of the grommet 72 and thus is in open communication with the stainless steel bellows 62.
  • the tube 64 extends through the vacuum space 38 of the housing 32 and further through the opening 42 in the annular plate 40.
  • the sapphire tip 66 Located in the second end 76 of the tube 64 and fastened thereto with epoxy is the sapphire tip 66 which serves as a thermally conducting substrate for the SQUID chip 56.
  • the end 80 of the sapphire tip 66 as best shown in Figure 5, is fabricated with a flat or planar side surface 82 extending in parallel to the longitudinal axis of the sapphire tip 66.
  • the SQUID chip 56 is adhesively attached to the flat side surface 82 and is securely maintained thereon during the operation of the scanning SQUID microscope 30.
  • cryogenic medium 36 from the cryogen containing portion 34 is supplied to the sapphire tip 66 through the stainless steel bellows 62 and the tube 64 to permit heat exchange between the
  • the distance between the SQUID chip and the window 50 may be as great as 2-3 millimeters or they may be contiguous in relation to each other.
  • the construction of the scanning SQUID microscope 30 permits maintenance of the SQUID chip temperature at 77°K while allowing for minute separation between the SQUID chip 56 and a room temperature sample 84, also referred herein as the object under investigation.
  • the sample 84 is positioned outside of the housing 32 of the scanning SQUID microscope 30 on a scanning stage 88 schematically shown in Figure 4 which is capable of movement in the three mutually perpendicular directions X, Y and Z.
  • the stage is motorized and provides positioning accuracy of about one micron or better.
  • the scanning stage 88 and mechanism moving such is known to those skilled in the art and is not described herein in detail.
  • the stage 88 is moved by the stepper motors 90 for driving the stage 88 in X and Y directions. It is preferable to mount the motors 90 as far as possible from the SQUID sensor (about 50 cm) and to envelop them in an eddy-current magnetic shield in order to shield the SQUID sensor from undesirable magnetic fields produced by the motors 90.
  • the motors 90 are mechanically coupled to micrometers.
  • the motors 90 are magnetically noisy, however, stepper motors and micrometers are used since they provide sufficient positioning accuracy.
  • a computer or processor 92 with controlling software and peripherals for operating the motors is used to operate the scanning stage 88 in the scanning SQUID microscope of the present invention.
  • the thermally conducting sapphire tip 66 may be approximately 1" long with a 0.25" diameter.
  • the SQUID chip 56 may consist of a single 200 nm thick layer 94 of YBa 2 Cu 3 0 7 patterned on a 500 micron thick SrTi0 3 bi-crystal substrate 96, as best shown in FIGS. 5 and 8.
  • the SQUID sensor 98 has a generally rectangular shape with the inner hole having widths approximating 10 microns and heights approximately 40 microns and with the outer approximate dimensions having widths of 30 microns and heights of 60 microns.
  • the modulation and flux feedback line 100 is patterned near the SQUID sensor 98 on the same substrate 96 using photolithographic printing techniques known in the art. After the patterns of the SQUID sensor 98 and modulation and feedback line 100 are formed on the substrate 96, the substrate 96 is cut into substantially rectangular pieces with the dimensions about 1.5 mm wide and 5 mm long.
  • the SQUID chip 56 is glued to the sapphire tip 66 with the substrate 96 affixed to the flat side surface 82, as best shown in FIG. 5. After the epoxy is cured, the end 104 of the SQUID chip 56 is polished down to about 800 microns width or smaller in order that the sapphire tip 66 can be mounted into the window 50. During this process, the end 104 of the SQUID chip is polished back, so that the SQUID is as close as possible to the end of the chip, preferably within a few microns.
  • Fabrication of the modulation and feedback line 100 directly on the SQUID chip provides an increased mutual inductance between the SQUID sensor 98 and line 100 thus enhancing the magnetic flux coupling into the SQUID for maintaining a flux-locked loop or for applying the read-out flux required for imaging circuitries of the scanning SQUID microscope of the present invention.
  • the substrate 96 is large enough (1.5 mm x 5 mm), the area thereon devoid of the SQUID sensor 98 and modulation and feedback line 100 constitutes a large enough area to provide larger contact areas 120 that makes the contact with bias and read-out wiring 102 easier and substantially reduces the contact resistance of the device.
  • the window 50 and the end 104 of the substrate 96 are aligned by moving the window 50 by means of the adjusting nuts 86 or screws 58.
  • the sample 84 on the scanning stage 88 is leveled with respect to the window 50 to insure that the separation between the sample and the SQUID sensor does not change during the scan as well as for achieving a small separation between the sample and the SQUID sensor.
  • This operation is performed by moving the stage 88 in the Z direction, shown in FIG. 4, either manually or automatically under the control of the computer 92. This operation is known to those skilled in the art and is not intended to be discussed in detail herein.
  • individual raster scan lines are acquired by scanning the sample with the SQUID sensor in, for example, the X direction while simultaneously recording in the computer 92 the X coordinates (read from the motor-control board 114) and the relevant magnetic field measured (read from the SQUID read-out electronics 106).
  • the process is further repeated for the sequence of Y values, by scanning the sample in the Y direction to construct a 2-dimensional image of the surface of the sample 84.
  • the SQUID chip 56 having its substrate thereof oriented perpendicularly to the X-Y plane (scanning plane) is positioned a distance Z 0 from the surface 110 of the sample 84 and is scanned first in the X direction and then in the Y direction along the surface 110.
  • the SQUID sensor detects the tangential component B x of the magnetic field B as opposed to detection of normal component B z of the magnetic field generated by the sample in the scanning SQUID microscopes of the prior art.
  • the spatial resolution of the scanning SQUID microscope depends on the detected magnetic field averaged over the area of a SQUID sensor projecting onto the sample plane. As best shown in FIGS. 7 and 5, the projection of the SQUID sensor 98 on the sample surface 110 is negligible and is determined only by the thickness of the layer of YBa 2 Cu 3 0 7 deposited onto the substrate 96 of the
  • the spatial resolution in the scanning SQUID microscope of the present invention is substantially independent of the size of a SQUID chip which permits taking advantage of a substantially larger area of the SQUID chip, such as 1.5 mm x 5 mm, as opposed to the SQUID chip of the prior art. Due to the substantially larger area of the SQUID chip it is possible to fabricate the modulation-and- feedback line 100 on the same chip as the SQUID sensor 98. It is also possible to fabricate larger contact pads 120 on the substrate 96, thus reducing the contact resistance of the device and making the contact with the bias and read-out wires 102 easier to implement.
  • FIG. 7 shows the current density - squared vs. X values in the X direction of scanning when the SQUID sensor scans the sample in the X direction.
  • the spatial resolution is defined as the "whole width at half maximum" (FWHM) of the current density squared peak 112 generated by the current I flowing through the current path 108.
  • FWHM whole width at half maximum
  • the spatial resolution of the scanning SQUID microscope of the present invention defined as shown in FIG. 7 is higher than the spatial resolution of the conventional scanning SQUID microscope using the SQUID chips oriented in parallel to the sample plane.
  • the position of the scanning stage 88 is determined by reading positions of the stepper motors 90.
  • the control program of the computer 92 can read the stepper motor positions directly from a motor controller board 114 which may be mounted in the computer 92.
  • the readout electronics 106 acquires data from the SQUID sensor 98.
  • Both the SQUID output and the position of the stage 88 are converted into digital form and recorded in the computer 92. Once data has been acquired using a control program of the computer 92, it is converted into an image. In its raw form, the image data consists of a set of N line scans (Y values) intersected with
  • M line scans (X values), with one or more associated magnetic field values at each of the NxM points.
  • the data is first spatially regularized, i.e., linearly inte ⁇ olated into rectangular space grids. Then an image rendering program is used to assign a level of gray to each grid point.
  • the control program is well-known in the art and is not discussed in further detail.
  • the control program processes the received position signals from the motor controller 114, in synchronism with outputs of SQUID sensor read by the readout electronics 106 and derives therefrom the spatially resolved images of the physical properties of the object, such as for example, magnetic fields emanating from the surface of the sample 84, etc.
  • the chart in FIG. 9 shows the comparison of spatial resolution obtained from the SQUID microscope of prior art and the SQUID microscope of the present invention.
  • the spatial resolution obtained after applying a magnetic inverse technique, discussed in following paragraphs is plotted vs. the sample to SQUID separation.
  • the spatial resolution is defined as the "full width at half maximum" (FWHM) of the current-density-squared peak generated by a current flowing through the wire 108 of the sample 84, as shown in Figure 6.
  • trace i corresponds to the spatial resolution of the SQUID sensor with the side dimension - 100 microns.
  • Trace ii shows the spatial resolution from the SQUID microscope of the prior art with data sampling step of 5 microns. It is shown that for the prior art, the spatial resolution is limited to about 80 microns and is limited by the 100 micron size of the SQUID sensor even when the sample to SQUID separation is reduced to 20 microns.
  • Traces iii and iv show the spatial resolution for the SQUID microscope of the present invention with data sampling steps of 5 microns and 2 microns, respectively. The spatial resolution in the X-direction in these two traces is not limited by the size of the SQUID.
  • the spatial resolution obtained from the SQUID microscope of the present invention is 40 microns and 20 microns for the sampling steps of 5 microns and 2 microns, respectively, as compared with the spatial resolution obtained from the SQUID microscope of the prior art which is about 80 microns.
  • a magnetic inversion technique was applied which permits extraction of the current path from the magnetic field data obtained with the SQUID sensors.
  • the principles of the magnetic inversion technique is based on the Biot-Savart Law, which relates current density to magnetic field.
  • the two main magnetic inversion techniques are directed to the application of a Fourier transfonii and spatial filtering to the measured magnetic field.
  • the reduction of noise and the edge effect of the data can be eliminated by using an appropriate signal processing filter such as that disclosed in the International Publication #WO 00/20879.
  • J x and J y are x and y components of current density, respectively.
  • b z (k x ,k y ,z), j xx (k x ,k y ) and j y (k x ,k y ) are the two-dimensional Fourier transforms of the magnetic field and the current density, respectively.
  • the k,, and k y are the components of the spatial frequency vector k.
  • the z-component of the magnetic field B(x,y,z) is detected, therefore b z (k x ,k y ,z) is the Fourier transform of the data obtained from the prior SQUID microscope.
  • the signal processing filters can be applied to the Eqs. (5) and (6) to eliminate undesired noise and edge effect of the data. Taking an inverse Fourier the current-density-squared is found which is the sum of each squared component.
  • Signal processing filters can be also applied to Eq. (7) to eliminate undesired noise and edge effects of the data. Specifically from Eq. (2), only the y- component of the current density generates B x (x,y,z), so the signal from the Fourier transform in Eq. (7) will be mostly along k ⁇ -direction. The appropriate signal processing filter, therefore, maintains the signal along the k ⁇ -direction and eliminates the off-l -axis signals which are mostly noise.
  • the Inverse Fourier transform of filtered Eq. (7) permits the obtaining of J y (x,y). Note that current- density-squared is the square of J y (x,y) for the X-SQUID.
  • any real SQUID has a non-zero pickup lop area over which the magnetic field must be integrated to get the total flux in the SQUID loop.
  • This integration is essentially a process that results in the SQUID output being proportional to the average field over the area of the SQUID loop. In the case of proportional to the average field over the area of the SQUID loop. In the case of the z-SQUID, this averaging causes blurring of the current sources that is not removed by the above magnetic inverse technique.
  • bjk ⁇ ⁇ z) is the Fourier transform of the magnetic field averaged over the SQUID loop (which is directly related to the output of the SQUID feedback output)
  • h the height of the SQUID loop in the z-direction
  • z the vertical distance between the current carrying region and the closest edge of the SQUID.
  • the enhanced spatial resolution of the imaging is attained wherein the spatial resolution is not limited to the size of the SQUID chip. Due to the new structure of the scanning SQUID microscope, not only an increased spatial resolution is obtained, but improvement to the SQUID sensor itself can be found by fabricating modulation and feedback lines directly on the same substrate with the SQUID sensor in one technological process, thus increasing the mutual inductance between the SQUID sensor and the modulation and feedback lines, as well as simplifying the design of the overall scanning SQUID microscope.
  • the enlarged contact pads provide for reduced contact resistance of the device as well as simplifying the coupling of the bias and read-out wires to the SQUID chip.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

L'invention concerne un microscope (30) SQUID à balayage destiné à fournir des images à résolution spatiale des propriétés physiques d'un objet (84). Ledit microscope comprend : un capteur (56) SQUID agencé perpendiculairement au plan de l'objet observé, permettant de détecter une composante tangentielle du champ magnétique généré par l'objet. Pendant le balayage effectué par le capteur (56) SQUID, de l'objet (84) observé, le signal de position d'une unité d'interprétation de position, ainsi que des signaux de sortie appropriés du capteur (56) SQUID sont traités par une unité de traitement qui dérive à partir des données, des images à résolution spatiale des propriétés physiques de l'objet. L'orientation spécifique du capteur (56) SQUID par rapport au plan de l'objet (84) permet d'obtenir une zone plus grande de la puce SQUID sur laquelle la ligne de modulation et de rétroaction (100) peut être réalisée selon le même processus technologique, avec le capteur SQUID. De plus, des plages de contact (120) plus grandes assurent une résistance de contact inférieure et facilitent la formation d'un contact avec des fils de polarisation et des fils de lecture. .
EP01975166A 2001-09-14 2001-09-14 Microscope squid a balayage a resolution spatiale amelioree Withdrawn EP1425595A4 (fr)

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Application Number Priority Date Filing Date Title
PCT/US2001/026024 WO2003025603A1 (fr) 2001-09-14 2001-09-14 Microscope squid a balayage a resolution spatiale amelioree

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EP1425595A1 true EP1425595A1 (fr) 2004-06-09
EP1425595A4 EP1425595A4 (fr) 2008-04-16

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US8013599B2 (en) * 2004-11-19 2011-09-06 General Electric Company Methods and apparatus for testing a component
JP4775632B2 (ja) * 2005-10-21 2011-09-21 独立行政法人科学技術振興機構 Ｓｑｕｉｄ顕微鏡による画像の解析方法、及びｓｑｕｉｄ顕微鏡による画像の解析システム
WO2008043137A1 (fr) * 2006-10-09 2008-04-17 Commonwealth Scientific And Industrial Research Organisation Procédé et appareil pour positionner des nanoparticules
JP5261763B2 (ja) * 2008-04-17 2013-08-14 独立行政法人 宇宙航空研究開発機構 磁場測定による溶接箇所の検査方法
JP6311188B2 (ja) * 2014-07-01 2018-04-18 学校法人金沢工業大学 Ｓｑｕｉｄ顕微鏡

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000020879A1 (fr) * 1998-10-05 2000-04-13 University Of Maryland Imagerie utilisant le masquage et le filtrage de frequence spatiale

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63246688A (ja) * 1987-04-01 1988-10-13 Hitachi Ltd 磁束検出装置
JPH083520B2 (ja) * 1987-07-06 1996-01-17 三菱電機株式会社 超伝導磁気検出装置
JPH05297091A (ja) * 1992-04-23 1993-11-12 Fujitsu Ltd 生体磁気計測装置
JPH06109820A (ja) * 1992-09-25 1994-04-22 Hitachi Ltd ３次元検出コイル
US5786690A (en) * 1994-08-18 1998-07-28 International Business Machines Corporation High resolution three-axis scanning squid microscope having planar solenoids
US5523686A (en) * 1994-08-30 1996-06-04 International Business Machines Corporation Probes for scanning SQUID magnetometers
US5894220A (en) * 1996-02-12 1999-04-13 University Of Maryland Apparatus for microscopic imaging of electrical and magnetic properties of room-temperature objects
DE19808985B4 (de) * 1997-03-07 2012-06-14 Hitachi, Ltd. Verfahren und Vorrichtung zur Biomagnetfeld-Messung
JP3133013B2 (ja) 1997-03-31 2001-02-05 セイコーインスツルメンツ株式会社 超伝導量子干渉素子およびそれを用いた非破壊検査装置
JP2000091653A (ja) * 1998-09-07 2000-03-31 Seiko Instruments Inc 超伝導量子干渉素子

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000020879A1 (fr) * 1998-10-05 2000-04-13 University Of Maryland Imagerie utilisant le masquage et le filtrage de frequence spatiale

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
No further relevant documents disclosed *
See also references of WO03025603A1 *

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