US5004726A
Expired / Lapsed
US
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Apparatus and methodology for the non-contact testing of materials for superconductivity by detecting odd harmonics above a threshold
Assignee: Philips North America LLC
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Filing: 1989-07-14
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Granted: 1991-04-02
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Expires: 2009-07-14
Abstract
Abstract Apparatus and methodology for the rapid and inexpensive characterization of superconducting materials. The method and apparatus induces an alternating magnetic field in the sample to be tested. If the material is a superconductor odd harmonics are generated in the alternating magnetic response of the material near the transition temperature. The superconducting transitions are manifested by a peak or peaks in the odd harmonic components of the alternating magnetic response as a function of temperature. The peaks of the harmonic components are detected to indicate the presence and number of superconducting transitions.
Inventors
- 👤 Avner A. Shaulov
- 👤 Samuel P. Herko
- 👤 Donald R. Dorman
- 👤 Rameshwar N. Bhargava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:42
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/12; G01R33/1238; Y; Y10; Y10S; Y10S505/00; Y10S505/725; Y10S505/726; Y10S505/727; Y10S505/786; Y10S505/825; Y10S505/842; Y10S505/843
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
97 words
A device for determining if a sample of material is a superconductor, comprising: means for inducing an alternating magnetic field in the sample of material to be tested; means for measuring the amplitude of the odd numbered harmonic component of the magnetic field induced in the sample to be tested; means connected to said measuring means for determining if the amplitude of the odd numbered harmonic has exceeded a predetermined threshold amplitude; and means connected to said amplitude determining means for indicating that the threshold amplitude has been exceeded to indicate that a superconducting transition has occurred.
Claim 2
Independent Claim
97 words
A device for determining if a sample of material is a superconductor, comprising: means for inducing an alternating magnetic field in the sample of material to be tested; means for measuring the amplitude of the odd numbered harmonic component of the magnetic field induced in the sample to be tested; means connected to said measuring means for determining if the amplitude of the odd numbered harmonic has exceeded a predetermined threshold amplitude; and means connected to said amplitude determining means for indicating that the threshold amplitude has been exceeded to indicate that a superconducting transition has occurred.
Claim 3
Dependent Claim
27 words
The device as claimed in claim 1 further including means for counting the number of times the threshold amplitude has been exceeded as the sample temperature changes.
Claim 4
Dependent Claim
20 words
The device as claimed in claim 1 wherein said means for inducing an alternating magnetic field comprise a magnetic coil.
Claim 5
Dependent Claim
48 words
The device as claimed in claim 1 wherein said means for measuring the odd numbered harmonic component of the magnetic field comprise a balanced coil, one side of said balanced coil holding the sample to be measured, the other side of said balanced coil being a reference coil.
Claim 6
Dependent Claim
17 words
The device as claimed in claim 1 wherein the odd numbered harmonic component is the third harmonic.
Claim 7
Dependent Claim
19 words
The device as claimed in claim 1 wherein the alternating magnetic field has a frequency of about 20 kHz.
Claim 8
Independent Claim
99 words
A method for determining if a sample of material is a superconductor comprising the steps of: varying the temperature of the sample of material through its critical temperature (T C ); applying an alternating magnetic field to the sample to be tested; measuring the odd numbered harmonic component of the magnetic field induced in the sample to be tested; comparing the amplitude of the odd numbered harmonic component with a predetermined amplitude to determine if the predetermined amplitude has been exceeded; and indicating that the threshold amplitude has been exceeded to thereby indicate that a superconducting transition has occurred.
Claim 9
Independent Claim
99 words
A method for determining if a sample of material is a superconductor comprising the steps of: varying the temperature of the sample of material through its critical temperature (T C ); applying an alternating magnetic field to the sample to be tested; measuring the odd numbered harmonic component of the magnetic field induced in the sample to be tested; comparing the amplitude of the odd numbered harmonic component with a predetermined amplitude to determine if the predetermined amplitude has been exceeded; and indicating that the threshold amplitude has been exceeded to thereby indicate that a superconducting transition has occurred.
Claim 10
Dependent Claim
30 words
The method as claimed in claim 7 further including the step of counting the number of times the predetermined amplitude has been exceeded as the temperature of the sample increases.
Claim 11
Dependent Claim
30 words
The method as claimed in claim 7 wherein the step of applying the alternating magnetic field to the sample to be tested comprises disposing said sample in a magnetic coil.
Claim 12
Dependent Claim
16 words
The method as claimed in claim 7 wherein the harmonic component measured is the third harmonic.
Claim 13
Dependent Claim
19 words
The method as claimed in claim 7 wherein the alternating magnetic field is on the order of 20 kHz.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |