MAGNETOMETRY USING SQUID
FERNANDO L. A. MACHADO
Departamento de Física, UFPE, Cidade Universitária, 50670-901 Recife, PE.
Presented by ANTONIO CID B. DEARAÚJO
Superconducting Quantum Interference Device (SQUID) is by far the most sensitive device ever built. It is a magnetic flux detector that can be used to measure magnetic field as low as few femtoTesla. Because of its high sensitivity, SQUID are being employed in detecting magnetic field generated by neural brain activity, noninvasive detection of metallic pieces inside the human body, nondestructive evaluation of corrosion and flaws, and in characterizing magnetic properties of materials, just to list few applications. Perhaps, the main limitation to replace most of the available magnetic sensors with SQUID's is the need of using liquid helium to operate them. However, with the recent progress made in the high temperature superconductor research field, there are SQUID being built that operate with liquid nitrogen and this makes them even more attractive.
Nowadays, there is a couple of companies around the world which sales SQUID magnetometers. However, they are too dedicated with almost no flexibility, the price is still too high and it is quite difficult to get maintenance when they fail. Another drawback is that these systems are true black boxes, not allowing graduate students and technicians to be trained in this very important technology. In my talk, I will describe a homemade magnetometer that uses a SQUID as the sensing element to investigate magnetic properties of materials. Our SQUID system operates from room temperature down to 1.5 K in a superconducting solenoid that generates magnetic field as high as 8 T. The SQUID system is particularly important when only a small amount of the magnetic material is available or to investigate system that presents weak magnetism. Some results of the magnetic studies made in magnetic polymers, thin-films and manganites will also be presented. (May 24, 2002).
Publication Dates
-
Publication in this collection
09 Oct 2002 -
Date of issue
Sept 2002
