EPSRC Reference: |
GR/L15821/01 |
Title: |
TORQUE MAGNETOMETRY OF SUPERCONDUCTORS |
Principal Investigator: |
Campbell, Professor AM |
Other Investigators: |
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Researcher Co-Investigators: |
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Project Partners: |
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Department: |
Engineering |
Organisation: |
University of Cambridge |
Scheme: |
Standard Research (Pre-FEC) |
Starts: |
01 September 1996 |
Ends: |
31 August 1997 |
Value (£): |
20,022
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EPSRC Research Topic Classifications: |
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EPSRC Industrial Sector Classifications: |
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Related Grants: |
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Panel History: |
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Summary on Grant Application Form |
We propose to use all the facilities here to probe the phase transition in the vortex lattice in several different ways. We will continue our AC susceptibility measurements, and we expect John Loram's specific heat apparatus to be producing results in a magnetic field very shortly. Prof. Farrell's contribution will be to use very sensitive torque magnetometers. Prof. Farrell has now constructed a similar system and is beginning to get results. This technology will be transferred to the UK and used in the IRC. The advantage of torque magnetometry over a VSM and a SQUID is that no sample movement occurs, so that the presence of irreversibility can be detected at a much lower level. Measurements will be made on the same crystals by different people, but all will be within the IRC so that inconsistencies can be ironed out on the spot. A second set of experiments will explore the importance of c axis conductivity to the irreversibility line. We have made a series of V-I characteristics with various arrangements of current inputs and contacts in virgin and irradiated crystals to see whether the c axis resistivity goes to zero at the same point as the ab axis resistivity. This is not straightforward as the extreme anisotropy of BSCCO makes it difficult to ensure that the ab resistivity is not dominated by a small section of c axis currents. Also the resistivity goes to zero in a roughly Arrhenius type of behaviour, so that there is not zero resistance point. These experiments are proving extremely productive but would be greatly enhanced with torque magnetometry. This can explore far lower voltage levels than a direct measurement and the currents are induced, so that contact problems are avoided.
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Key Findings |
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Potential use in non-academic contexts |
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Impacts |
Description |
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Summary |
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Date Materialised |
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Sectors submitted by the Researcher |
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Project URL: |
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Further Information: |
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Organisation Website: |
http://www.cam.ac.uk |