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SQUID is ..
The Superconducting Quantum Interference Device (SQUID) magnetometer is one of the most effective and sensitive ways of measuring magnetic properties and it is the only method which allows to directly determine the overall magnetic moment of a sample in absolute units.
The detector …
The SQUID detector consists of two superconductors separated by thin insulating layers to form two parallel Josephson junctions. The electrical current density through a weak electric contact between two superconductors depends on the phase difference Δφ of the two (S)uperconducting (Q)uantum wave functions. The time derivative of Δφ is correlated with the voltage across the contact. The phase difference Δφ [(I)nterference] is influenced by the magnetic flux Φ through (D)evice. The SQUID detector can therefore be used to convert magnetic flux Φ into electrical voltage.
The experiment …
If a sample is moved up and down in a magnet it produces an alternating magnetic flux Φ in a superconducting pick-up coil. The coil and the SQUID antenna, are part of a superconducting circuit transferring the magnetic flux Φ from the sample to the SQUID device which is located away from the sample in a liquid helium bath. The SQUID acts as a magnetic flux-to-voltage converter, where voltage (signal) produced is amplified and read out by the instruments electronics.
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SQUID is an analysis tool for solid crystalline, semi-crystalline and amorphous materials.
Two general methods to acquire research information are available to you
1) You may submit a sample to us for investigation
2) You may collect your own data.
If you choose option two then you must first be qualified to use the instrumentation, undertake safety training and go through instrument usage training.
You are qualified to use the instrumentation if you are an employee of Texas A & M University and are covered by workman's compensation insurance.
Visiting researchers are generally covered. Please check with your principle investigator to be sure.
See NEW USERS for full details.
We have been partially funded by the National Science Foundation.
Academic users should submit samples to us in person or by post.
Users are encouraged to follow the steps outlined in the sample submission section of this web site.
We will gladly work with all commercial users.
Please see the user All Users section of this web site for more details.
Users are
encouraged to follow the steps outlined in the sample
submission section of this web site.
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