The Quantum Design MPMS 5XL SQUID uses a Superconducting Quantum Interference Device (SQUID) Magnetometer to monitor very small changes in magnetic flux and so discover the magnetic properties of samples. It is extremely sensitive for all kinds of AC and DC magnetic measurements.
The SQUID detects and measures the Magnetic Moment of the sample. From this the magnetization and magnetic susceptibility can be determined.
Applications of the SQUID magnetometer include measurements of small quantities of paramagnetic ions, characterization of all kinds of magnetic materials, and quantitative determination of the number of unpaired electrons in samples. The MPMS-XL provides solutions for a unique class of sensitive magnetic measurements in key areas such as high-temperature superconductivity, biochemistry, and magnetic recording media. .
Data can be collected between H = O to ± 50 kOe and T = 1.7 K to 400 K. The maximum sensitivity of the instrument is in the range of 10-9 emu.
Samples are typically 20 to 40 mg but strongly magnetic materials can be measured with less material.
Two documents in particular may help a beginning SQUID user. Fundamentals of Magnetism for MPMS covers the background Physics and introduces the instrument well. It may seem out of date, but the fundamentals have not changed. The other recommended document is called MPMS MultiVu user manual. The original version is over 180 pages but an abbreviated version called MPMS MultiVu user manual short is a more manageable 69 pages.
QD had a training CD Rom with much more extensive information that is available in the lab.
Quantum Design has considerable information about the SQUID at thier web page: http://www.qdusa.com/products/mpms.html and http://www.qdusa.com/techsupport/index.html.